2022/04/12 更新

写真a

マツオ タロウ
松尾 太郎
MATSUO Taro
所属
大学院理学研究科 理学専攻 物理学第二 准教授
大学院担当
大学院理学研究科
学部担当
理学部 物理学科
職名
准教授
連絡先
メールアドレス
プロフィール
私は「生命とは何か?、なぜ、私たちは誕生したのか?」という問いに対して、宇宙から地球を俯瞰しながら、また地球を一つの生命が存在する惑星として捉えながら、その問いに迫りたいと考えています。その問いに迫る第一歩が宇宙における生命探査だと考えています。しかし、その実現には多くの技術的課題が残されています。私は、このような技術的課題にはブレークスルーが欠かせないと考えており、新しいアイデアやアプローチを試行錯誤しながら、実現したいと考えています。新しい学問の誕生には、一つの学問からの発展では困難です。従来の学問の領域・壁を超えて、生物学・植物学・惑星科学の研究者らと連携しながら、この問いに迫りたいと考えています。最終的には、様々な国や人との交流を通して、そのフロンティアを開拓していきます。
外部リンク

学位 1

  1. 博士(理学) ( 2008年3月   名古屋大学 ) 

研究キーワード 5

  1. 地球型惑星候補の大気分光のための高コントラスト分光撮像

  2. 地球型系外惑星候補の大気分光

  3. 太陽系外惑星の惑星形成

  4. 編隊飛行型赤外線宇宙干渉計

  5. 食惑星の大気分光のための超精密分光

研究分野 1

  1. 自然科学一般 / 天文学  / 宇宙生物学, 分光

経歴 3

  1. 名古屋大学   理学部 物理学科   准教授

    2019年11月 - 現在

  2. NASA Ames Research Center   Space Science and Astrobiology Division   Visiting Researcher

    2018年6月 - 現在

  3. 大阪大学   大学院理学研究科 宇宙地球科学専攻   助教

    2015年10月 - 2019年10月

所属学協会 1

  1. 天文学会

    2010年4月 - 現在

委員歴 5

  1. 光赤外天文連絡会   2030年代の光赤外将来計画委員会  

    2018年4月 - 現在   

  2. 光赤外天文連絡会   2030年代の光赤外線スペース計画委員会  

    2017年4月 - 2018年3月   

  3. 国立天文台   188cm望遠鏡観測時間割当委員会  

    2014年4月 - 2018年3月   

  4. Thirty Meter Telescope   Thirty Meter Telescope, International Science Development Team  

    2013年4月 - 2017年3月   

  5. Thirty Meter Telescope   International Science Advisory Committee  

    2013年4月 - 2017年3月   

 

論文 38

  1. High spatial resolution spectral imaging method for space interferometers and its application to formation flying small satellites 査読有り

    Taro Matsuo, Satoshi Ikari, Hirotaka Kondo, Sho Ishiwata, Shinichi Nakasuka, Tomoyasu Yamamuro

    Journal of Astronomical Telescopes, Instruments, and Systems   8 巻   2022年2月

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    担当区分:筆頭著者, 責任著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: https://doi.org/10.1117/1.JATIS.8.1.015001

  2. Densified Pupil Spectrograph as High-precision Radial Velocimetry: From Direct Measurement of the Universe's Expansion History to Characterization of Nearby Habitable Planet Candidates

    Matsuo T., Greene T.P., Qezlou M., Bird S., Ichiki K., Fujii Y., Yamamuro T.

    Astronomical Journal   163 巻 ( 2 )   2022年2月

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    記述言語:日本語   出版者・発行元:Astronomical Journal  

    The direct measurement of the universe's expansion history and the search for terrestrial planets in habitable zones around solar-type stars require extremely high-precision radial-velocity measures over a decade. This study proposes an approach for enabling high-precision radial-velocity measurements from space. The concept presents a combination of a high-dispersion densified pupil spectrograph and a novel line-of-sight monitor for telescopes. The precision of the radial-velocity measurements is determined by combining the spectrophotometric accuracy and the quality of the absorption lines in the recorded spectrum. Therefore, a highly dispersive densified pupil spectrograph proposed to perform stable spectroscopy can be utilized for high-precision radial-velocity measures. A concept involving the telescope's line-of-sight monitor is developed to minimize the change of the telescope's line of sight over a decade. This monitor allows the precise measurement of long-term telescope drift without any significant impact on the Airy disk when the densified pupil spectra are recorded. We analytically derive the uncertainty of the radial-velocity measurements, which is caused by the residual offset of the lines of sight at two epochs. We find that the error could be reduced down to approximately 1 cm s-1, and the precision will be limited by another factor (e.g., wavelength calibration uncertainty). A combination of the high-precision spectrophotometry and the high spectral resolving power could open a new path toward the characterization of nearby non-transiting habitable planet candidates orbiting late-type stars. We present two simple and compact highly dispersed densified pupil spectrograph designs for cosmology and exoplanet sciences.

    DOI: 10.3847/1538-3881/ac397b

    Scopus

  3. Polarimetric signature of the oceans as detected by near-infrared Earthshine observations

    Takahashi J., Itoh Y., Matsuo T., Oasa Y., Bach Y.P., Ishiguro M.

    Astronomy and Astrophysics   653 巻   2021年9月

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    記述言語:日本語   出版者・発行元:Astronomy and Astrophysics  

    Context. The discovery of an extrasolar planet with an ocean has crucial importance in the search for life beyond Earth. The polarimetric detection of specularly reflected light from a smooth liquid surface is anticipated theoretically, though the polarimetric signature of Earth's oceans has not yet been conclusively detected in disk-integrated planetary light. Aims. We aim to detect and measure the polarimetric signature of the Earth's oceans. Methods. We conducted near-infrared polarimetry for lunar Earthshine and collected data on 32 nights with a variety of ocean fractions in the Earthshine-contributing region. Results. A clear positive correlation was revealed between the polarization degree and ocean fraction. We found hourly variations in polarization in accordance with rotational transition of the ocean fraction. The ratios of the variation to the typical polarization degree were as large as ~0.2-1.4. Conclusions. Our observations provide plausible evidence of the polarimetric signature attributed to Earth's oceans. Near-infrared polarimetry may be considered a prospective technique in the search for exoplanetary oceans.

    DOI: 10.1051/0004-6361/202039331

    Scopus

  4. Detecting Atmospheric Molecules of Nontransiting Temperate Terrestrial Exoplanets Using High-resolution Spectroscopy in the Mid-infrared Domain

    Fujii Y., Matsuo T.

    Astronomical Journal   161 巻 ( 4 )   2021年4月

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    記述言語:日本語   出版者・発行元:Astronomical Journal  

    Motivated by the development of high-dispersion spectrographs in the mid-infrared (MIR) range, we study their application to the atmospheric characterization of nearby nontransiting temperate terrestrial planets around M-type stars. We examine the detectability of CO2, H2O, N2O, and O3 features in high-resolution planetary thermal emission spectra at 12-18 μm assuming an Earth-like profile and a simplified thermal structure. The molecular line width of such planets can be comparable to or broader than the Doppler shift due to the planetary orbital motion. Given the likely difficulty in knowing the high-resolution MIR spectrum of the host star with sufficient accuracy, we propose observing the target system at two quadrature phases and extracting the differential spectra as the planetary signal. In this case, the signals can be substantially suppressed compared with the case where the host star spectrum is perfectly known, as some parts of the spectral features do not remain in the differential spectra. Despite this self-subtraction, the CO2 and H2O features of nearby (≲5 pc) systems with mid-/late-M host stars would be feasible with a 6.5 m class cryogenic space telescope, and orbital inclination could also be constrained for some of them. For CO2 and N2O in a 1 bar Earth-like atmosphere, this method would be sensitive when the mixing ratio is 1-103 ppm. The detectability of molecules except O3 is not significantly improved when the spectral resolution is higher than R10,000, although the constraint on the orbital inclination is improved. This study provides some benchmark cases useful for assessing the value of MIR high-resolution spectroscopy in terms of characterization of potentially habitable planets.

    DOI: 10.3847/1538-3881/abe129

    Scopus

  5. Detecting Atmospheric Molecules of Nontransiting Temperate Terrestrial Exoplanets Using High-resolution Spectroscopy in the Mid-infrared Domain 査読有り

    Y. Fujii T. Matsuo

    Astronomical Journal   161 巻   頁: 180   2021年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: https://doi.org/10.3847/1538-3881/abe129

  6. Spectroscopic fourth-order coronagraph for the characterization of terrestrial planets at small angular separations from host stars

    Matsuo T., Itoh S., Ikeda Y.

    Astronomical Journal   161 巻 ( 2 )   2021年2月

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    記述言語:日本語   出版者・発行元:Astronomical Journal  

    We propose a new approach for high-contrast imaging at the diffraction limit using segmented telescopes in a modest observation bandwidth. This concept, named "spectroscopic fourth-order coronagraphy,"is based on a fourth-order coronagraph with a focal-plane mask that modulates the complex amplitude of the Airy disk along one direction. While coronagraphs applying the complex amplitude mask can achieve the theoretical limit performance for any arbitrary pupils, the focal-plane mask severely limits the bandwidth. Here, focusing on the fact that the focal-plane mask modulates the complex amplitude along one direction, we noticed that the mask can be optimized for each spectral element generated by a spectrograph. We combine the fourth-order coronagraph with two spectrographs to produce a stellar spectrum on the focal plane and reconstruct a white pupil on the Lyot stop. Based on the wave-front analysis of an optical design applying an Offner-type imaging spectrograph, we found that the achievable contrast of this concept is 10-10-10 at 1.2-1.5 times the diffraction limit over the wavelength range of 650-750 nm for the entrance pupil of the LUVOIR telescope. Thus, this coronagraph concept could bring new habitable planet candidates not only around G- and K-type stars beyond 20-30 pc but also around very nearby M-type stars. This approach potentially promotes the characterization of the atmospheres of nearby terrestrial planets with future on- and off-axis segmented large telescopes.

    DOI: 10.3847/1538-3881/abd248

    Web of Science

    Scopus

  7. Mid-infrared spectrometer and camera for the Origins Space Telescope

    Sakon I., Roellig T.L., Ennico-Smith K., Matsuo T., Ikeda Y., Yamamuro T., Enya K., Wada T., Kawada M., Takahashi A., Sarugaku Y., Fujishiro N., Murakami N., Nishikawa J., Kotani T., Goda S., Ido M., Itoh S., Tsuboi T., Sumi T., Kamiura M., Manome T., Iida N., Yanagibashi K., Greene T., Helvensteijn B., Hofland L., Johnson R., Kashani A., Quigley E., McMurray R., Inami H., Burgarella D.

    Journal of Astronomical Telescopes, Instruments, and Systems   7 巻 ( 1 )   2021年1月

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    記述言語:日本語   出版者・発行元:Journal of Astronomical Telescopes, Instruments, and Systems  

    The mid-infrared spectrometer and camera transit spectrometer (MISC-T) is one of the three baseline instruments for Origins Space Telescope (Origins) and provides the capability to assess the habitability of nearby exoplanets and search for signs of life. MISC-T employs a densified pupil optical design, and HgCdTe and Si:As detector arrays. This optical design allows the instrument to be relatively insensitive to minor line-of-sight pointing drifts and telescope aberrations, and the detectors do not require a sub-Kelvin refrigerator. MISC-T has three science spectral channels that share the same field-of-view by means of beam splitters, and all channels are operated simultaneously to cover the full spectral range from 2.8 to 20 μm at once with exquisite stability and precision (<5 ppm between 2.8 to 11 μm, <20 ppm between 11 and 20 μm). A Lyot-coronagraph-based tip-tilt sensor located in the instrument fore-optics uses the light reflected by a field stop, which corresponds to 0.3% of the light from the target, to send fine pointing information to the field steering mirror in the Origins telescope. An additional MISC Wide Field Imager (WFI) is studied as an upscope option for the Origins. MISC-WFI offers a wide field imaging (3′ × 3′) and low-resolution spectroscopic capability with filters and grating-prisms (grisms) covering 5 to 28 μm. The imaging capability of the MISC-WFI will be used for general science objectives. The low-resolution spectroscopic capability in MISC-WFI with a resolving power R (= λ/Δλ) of a few hundreds will be used to measure the mid-infrared dust features and ionic lines at z up to 1/41 in the Origins mission's Rise of Metals and Black Hole Feedback programs. The MISC-WFI also serves as a focal plane pointing and guiding instrument for the observatory, including when the MISC-T channel is performing its exoplanet spectroscopy observations.

    DOI: 10.1117/1.JATIS.7.1.011013

    Scopus

  8. Mid-infrared detector development for the Origins Space Telescope 招待有り 査読有り 国際共著

    T. Roellig, C. MucMarty, T. Greene, T. Matsuo, I. Sakon, J. Staguhn

    Journal of Astronomical Telescopes, Instruments, and Systems   6 巻   2020年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1117/1.JATIS.6.4.041503

  9. OGLE-2017-BLG-0406: Spitzer Microlens Parallax Reveals Saturn-mass Planet Orbiting M-dwarf Host in the Inner Galactic Disk

    Hirao Y., Bennett D.P., Ryu Y.H., Koshimoto N., Udalski A., Yee J.C., Sumi T., Bond I.A., Shvartzvald Y., Abe F., Barry R.K., Bhattacharya A., Donachie M., Fukui A., Itow Y., Kondo I., Alex Li M.C., Matsubara Y., Matsuo T., Miyazaki S., Muraki Y., Nagakane M., Ranc C., Rattenbury N.J., Suematsu H., Shibai H., Suzuki D., Tristram P.J., Yonehara A., Skowron J., Poleski R., Mróz P., Szymański M.K., Soszyński I., Kozłowski S., Pietrukowicz P., Ulaczyk K., Rybicki K., Iwanek P., D. Albrow M., Chung S.J., Gould A., Han C., Hwang K.H., Jung Y.K., Shin I.G., Zang W., Cha S.M., Kim D.J., Kim H.W., Kim S.L., Lee C.U., Lee D.J., Lee Y., Park B.G., Pogge R.W., Beichman C.A., Bryden G., Novati S.C., Carey S., Gaudi B.S., Henderson C.B., Zhu W., Bachelet E., Bolt G., Christie G., Hundertmark M., Natusch T., Maoz D., McCormick J., A. Street R., Tan T.G., Tsapras Y., Jørgensen U.G., Dominik M., Bozza V., Skottfelt J., Snodgrass C., Ciceri S., Jaimes R.F., Evans D.F., Peixinho N., Hinse T.C., Burgdorf M.J., Southworth J., Rahvar S., Sajadian S., Rabus M., Essen C.V., Fujii Y.I., Campbell-White J., Lowry S., Helling C., Mancini L., Haikala L., Kandori R.

    Astronomical Journal   160 巻 ( 2 )   2020年8月

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    記述言語:日本語   出版者・発行元:Astronomical Journal  

    We report the discovery and analysis of the planetary microlensing event OGLE-2017-BLG-0406, which was observed both from the ground and by the Spitzer satellite in a solar orbit. At high magnification, the anomaly in the light curve was densely observed by ground-based-survey and follow-up groups, and it was found to be explained by a planetary lens with a planet/host mass ratio of q = 7.0 × 10-4 from the light-curve modeling. The ground-only and Spitzer-"only"data each provide very strong one-dimensional (1D) constraints on the 2D microlens parallax vector πE. When combined, these yield a precise measurement of πE and of the masses of the host equation presented and planet M planet = 0.41 ± 0.05 M Jup. The system lies at a distance D L = 5.2 ± 0.5 kpc from the Sun toward the Galactic bulge, and the host is more likely to be a disk population star according to the kinematics of the lens. The projected separation of the planet from the host is a? = 3.5 ± 0.3 au (i.e., just over twice the snow line). The Galactic-disk kinematics are established in part from a precise measurement of the source proper motion based on OGLE-IV data. By contrast, the Gaia proper-motion measurement of the source suffers from a catastrophic 10σ error.

    DOI: 10.3847/1538-3881/ab9ac3

    Web of Science

    Scopus

    arXiv

  10. Fourth-order Coronagraph for High-contrast Imaging of Exoplanets with Off-axis Segmented Telescopes 査読有り

    Itoh S., Matsuo T.

    Astronomical Journal   159 巻 ( 5 )   2020年5月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Astronomical Journal  

    We propose a coronagraphic system with fourth-order null for off-axis segmented telescopes, which is sufficiently insensitive to the telescope pointing errors and finite angular diameter of the host star to enable high-contrast imaging of potentially habitable planets. The inner working angle of the coronagraphic system is close to 1λ/D, and there is no outer limit. The proposed coronagraphic system is made up of a new focal plane mask and an optimized Lyot stop with the second-order null. The new focal plane mask is an extension of the band-limited masks with a phase modulation. We construct a coronagraphic system with fourth-order null by placing two of the new coronagraph systems in succession to be orthogonal to each other. The proposed system is limited to narrow-band usage. The characteristics of the proposed coronagraph system are derived analytically, which includes (1) the leak of stellar lights due to the finite stellar diameter and pointing jitter of a telescope, and (2) the peak throughput. We achieve the performance simulations of this coronagraphic system based on these analytical expressions, considering a monochromatic light of 0.75 μm and an off-axis primary mirror with a diameter of 8.5 m. Thanks to the wide working area of the mask, the result shows that terrestrial planets orbiting K and G dwarfs can be detected under the condition that the telescope pointing jitter is less than 0.01λ/D ≈ 240 as. The proposed coronagraphic system is promising for the detection of potentially habitable planets with future space off-axis hexagonally segmented telescopes.

    DOI: 10.3847/1538-3881/ab811c

    Web of Science

    Scopus

    arXiv

  11. Optical Adjustment of the FITE Interferometer 査読有り

    Ayana Sasaki, Hiroshi Shibai, Taro Matsuo, Takahiro Sumi, Satoshi Itoh, Teruhira Ohyama, Yoshito Tani, Morito Saiki, Takahiro Tsuboi, Masanao Narita

    JOURNAL OF ASTRONOMICAL INSTRUMENTATION   9 巻 ( 1 )   2020年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WORLD SCIENTIFIC PUBL CO PTE LTD  

    We have developed a balloon-borne far-infrared interferometer, the Far-infrared Interferometric Telescope Experiment (FITE). The final goal of spatial resolution was one arcsec at 100 mu m. As a first step, we aimed to achieve a spatial resolution of five arcsecs at 155 mu m with a 6-m baseline. FITE is a two-beam interferometer like Michelsons stellar interferometer. Positions and attitudes of all mirrors required to have their alignment checked and possibly adjusted before launch and were checked during observation. We had to satisfy three requirements: the coincidence of the phases of each beam (wavefront error), image quality of the two beams at the (common) focus, and no optical path difference between the two beams for celestial objects. In order to achieve the former two requirements, we developed an interferometer adjustment system that used a newly-developed interferometer measurement instrument. This instrument adopted a Shack-Hartmann wavefront sensor to measure wavefront errors of the two off-axis parabolic mirrors, simultaneously. With this system, the adjustment of the FITE interferometer was carried out at the Alice Springs balloon base in Australia as the JAXA's Australia balloon experiment campaign of 2018. On-site adjustment was successful; wavefront errors of the two off-axis parabolic mirrors were 1.78 mu m and 4.99 mu m (peak-to-valley), and the Hartmann constant was 13 arcsecs. As for the optical path difference, we achieved the requirement by step-wise displacement of a folding plane mirror. Results satisfied the requirements for an interferometer designed for a wavelength of 155 mu m. Improvement of spatial resolution at far-infrared wavelengths is undoubtedly important for research on protoplanetary disks, circumstellar dust shells of late-type stars, and star-forming galaxies. The method we have developed is also useful for future space interferometers.

    DOI: 10.1142/S2251171720500026

    Web of Science

  12. OGLE-2013-BLG-0911Lb: A Secondary on the Brown-dwarf Planet Boundary around an M Dwarf 査読有り

    Miyazaki S., Sumi T., Bennett D.P., Bennett D.P., Udalski A., Shvartzvald Y., Street R., Bozza V., Bozza V., Yee J.C., Bond I.A., Rattenbury N., Koshimoto N., Suzuki D., Fukui A., Fukui A., Abe F., Bhattacharya A., Bhattacharya A., Barry R., Donachie M., Fujii H., Hirao Y., Itow Y., Kamei Y., Kondo I., Li M.C.A., Ling C.H., Matsubara Y., Matsuo T., Muraki Y., Nagakane M., Ohnishi K., Ranc C., Saito T., Sharan A., Shibai H., Suematsu H., Sullivan D.J., Tristram P.J., Yamakawa T., Yonehara A., Skowron J., Poleski R., Mróz P., Mróz P., Szymaski M.K., Soszyski I., Pietrukowicz P., Kozowski S., Ulaczyk K., Wyrzykowski , Friedmann M., Kaspi S., Maoz D., Albrow M., Christie G., Depoy D.L., Gal-Yam A., Gould A., Gould A., Gould A., Lee C.U., Fr C., Manulis I., McCormick J., Natusch T., Ngan H., Pogge R.W., Porritt I., Tsapras Y., Bachelet E., Hundertmark M.P.G., Dominik M., Bramich D.M., Cassan A., Jaimes R.F., Horne K., Schmidt R., Snodgrass C., Wambsganss J., Steele I.A., Menzies J., Mao S., Mao S., Mao S., Jørgensen U.G., Burgdorf M.J., Ciceri S., Novati S.C., D'Ago G., Evans D.F.

    Astronomical Journal   159 巻 ( 2 )   2020年2月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Astronomical Journal  

    We present the analysis of the binary-lens microlensing event OGLE-2013-BLG-0911. The best-fit solutions indicate the binary mass ratio of q ? 0.03, which differs from that reported in Shvartzvald et al. The event suffers from the well-known close/wide degeneracy, resulting in two groups of solutions for the projected separation normalized by the Einstein radius of s ? 0.15 or s ? 7. The finite source and the parallax observations allow us to measure the lens physical parameters. The lens system is an M dwarf orbited by a massive Jupiter companion at very close separation. Although the mass ratio is slightly above the planet-brown dwarf (BD) mass-ratio boundary of q = 0.03, which is generally used, the median physical mass of the companion is slightly below the planet-BD mass boundary of 13MJup. It is likely that the formation mechanisms for BDs and planets are different and the objects near the boundaries could have been formed by either mechanism. It is important to probe the distribution of such companions with masses of ?13MJup in order to statistically constrain the formation theories for both BDs and massive planets. In particular, the microlensing method is able to probe the distribution around low-mass M dwarfs and even BDs, which is challenging for other exoplanet detection methods.

    DOI: 10.3847/1538-3881/ab64de

    Web of Science

    Scopus

  13. High-resolution Near-infrared Polarimetry and Submillimeter Imaging of FS Tau A: Possible Streamers in Misaligned Circumbinary Disk System 査読有り

    Yi Yang, Eiji Akiyama, Thayne Currie, Ruobing Dong, Jun Hashimoto, Saeko S. Hayashi, Carol A. Grady, Markus Janson, Nemanja Jovanovic, Taichi Uyama, Takao Nakagawa, Tomoyuki Kudo, Nobuhiko Kusakabe, Masayuki Kuzuhara, Lyu Abe, Wolfgang Brandner, Timothy D. Brandt, Michael Bonnefoy, Joseph C. Carson, Jeffrey Chilcote, Evan A. Rich, Markus Feldt, Miwa Goto, Tyler D. Groff, Olivier Guyon, Yutaka Hayano, Masahiko Hayashi, Thomas Henning, Klaus W. Hodapp, Miki Ishii, Masanori Iye, Ryo Kandori, Jeremy Kasdin, Gillian R. Knapp, Jungmi Kwon, Julien Lozi, Frantz Martinache, Taro Matsuo, Satoshi Mayama, Michael W. Mcelwain, Shoken Miyama, Jun-Ichi Morino, Amaya Moro-Martin, Tetsuo Nishimura, Tae-Soo Pyo, Eugene Serabyn, Hiroshi Suto, Ryuji Suzuki, Michihiro Takami, Naruhisa Takato, Hiroshi Terada, Christian Thalmann, Edwin L. Turner, Makoto Watanabe, John P. Wisniewski, Toru Yamada, Hideki Takami, Tomonori Usuda, Motohide Tamura

    ASTROPHYSICAL JOURNAL   889 巻 ( 2 )   2020年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IOP PUBLISHING LTD  

    We analyzed the young (2.8 Myr-old) binary system FS Tau A using near-infrared (H-band) high -contrast polarimetry data from Subaru/HiCIAO and submillimeter CO (J = 2-1) line emission data from Atacama Large Millimeter/submillimeter Array (ALMA). Both the near-infrared and submillimeter observations reveal several clear structures extending to similar to 240 au from the stars. Based on these observations at different wavelengths, we report the following discoveries. One arm-like structure detected in the near-infrared band initially extends from the south of the binary with a subsequent turn to the northeast, corresponding to two bar-like structures detected in ALMA observations with an local standard of rest kinematic (LSRK) velocity of 1.19-5.64 km s(-1). Another feature detected in the near-infrared band extends initially from the north of the binary, relating to an arm-like structure detected in ALMA observations with an LSRK velocity of 8.17-16.43 km s(-1). From their shapes and velocities, we suggest that these structures can mostly be explained by two streamers that connect the outer circumbinary disk and the central binary components. These discoveries will be helpful for understanding the evolution of streamers and circumstellar disks in young binary systems.

    DOI: 10.3847/1538-4357/ab64f9

    Web of Science

    arXiv

  14. The mid-infrared spectrometer/camera (MISC) for the Origins Space Telescope 査読有り

    Sakon I., Roellig T.L., Ennico-Smith K., Matsuo T., Ikeda Y., Yamamuro T., Enya K.

    Proceedings of SPIE - The International Society for Optical Engineering   11443 巻   2020年

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Proceedings of SPIE - The International Society for Optical Engineering  

    The Mid-Infrared Spectrometer (Camera) transit spectrometer (MISC-T) is one of the baseline instruments studied for the Origins Space Telescope. MISC-T employs a novel densified pupil optical design and achieves exquisite stability and precision (<5ppm in 2.8 - 11μm, <20ppm in 11 - 20μm). It provides the Origins with the capability to assess the habitability of nearby exoplanets and search for signs of life. An additional MISC Wide Field Imager (MISC-WFI) is studied as an upsope option for the Origins. MISC-WFI offers an imaging and low-resolution spectroscopic capability for 5 - 28μm. The MISC WFI also serves as the focal plane pointing and guiding for the observatory.

    DOI: 10.1117/12.2561949

    Scopus

  15. Laboratory experiment of densified pupil spectrograph for the Origins Space Telescope 査読有り

    Matsuo T., Greene T.P., Johnson R.R., Mcmurray R.E., Roellig T., Ennico-Smith K., Helvensteijn B.P., Kashani A., Shibai H., Sumi T., Itoh S., Sakon I., Yamamuro T., Ikeda Y., Manome T., Iida N., Yanagibashi K., Kamiura M.

    Proceedings of SPIE - The International Society for Optical Engineering   11443 巻   2020年

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Proceedings of SPIE - The International Society for Optical Engineering  

    We report on the laboratory experiments of a densified pupil spectrograph designed for mid-infrared transit spectroscopy of exoplanets. We developed a testbed consisting of a blackbody infrared light source, a densified pupil spectrograph, and a prototype JWST Si:As Impurity Band Conduction (IBC) detector array to simulate observations of a planet's host star. In order to thermally stabilize the measurement system, we installed all of the components in a large cryogenic dewar and controlled the temperatures of the thermal source and the Si:As IBC detector. The characteristics of the spectrum formed on the detector were consistent with the designed values. The photometric precision of the densified pupil spectrograph was 14 ppm on average over the whole observing wavelength range of 8.5 to 10.5 μm. The systematic noise component of the spectrograph hidden behind the transit spectrograph was 11 ppm.

    DOI: 10.1117/12.2560421

    Scopus

  16. Identification of infrared-ring structures by convolutional neural network 査読有り

    Ueda S.

    Proceedings of SPIE - The International Society for Optical Engineering   11452 巻   2020年

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:Proceedings of SPIE - The International Society for Optical Engineering  

    DOI: 10.1117/12.2560830

    Scopus

  17. Photometric Precision of a Si:As Impurity Band Conduction Mid-infrared Detector and Application to Transit Spectroscopy 査読有り

    Taro Matsuo, Thomas P. Greene, Roy R. Johnson, Robert E. Mcmurray, Thomas L. Roellig, Kimberly Ennico

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC   131 巻 ( 1006 )   2019年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IOP PUBLISHING LTD  

    Transit spectroscopy is the most promising path toward characterizing nearby terrestrial planets at mid-infrared (3?30 ?m) wavelengths in the next 20 yr. The Spitzer Space telescope has achieved moderately good mid-infrared photometric precision in observations of transiting planets, but the intrinsic photometric stability of mid-IR detectors themselves has not been reported in the scientific or technical literature. Here, we evaluated the photometric precision of a James Webb Space Telescope Mid-Infrared Instrument prototype mid-infrared Si:As impurity band conduction detector, using time-series data taken under flood illumination. These measurements of photometric precision were conducted over periods of ?10 hr, representative of the time required to observe an exoplanet transit. After selecting multiple sub-regions with a size of 10 & xfffd;& x5e0;10 pixels and compensating for a gain change caused by our warm detector control electronics for the selected sub-regions, we found that the photometric precision was limited to 26.3 ppm at high co-added signal levels due to a gain variation caused by our warm detector control electronics. The photometric precision was improved up to 12.8 ppm after correcting for the gain drift. We also translated the photometric precision to the expected spectro-photometric precision (i.e., relative photometric precision between wavelengths), assuming that an optimized densified pupil spectrograph is used in transit observations. We found that the spectro-photometric precision of an optimized densified pupil spectrograph when used in transit observations is expected to be improved by the square root of the number of pixels per a spectral resolution element. At the high co-added signal levels, the total noise could be reduced down to 7 ppm, which was larger by a factor of 1.3 than the ideal performance that was limited by the Poisson noise and readout noise. The systematic noise hidden behind the simulated transit spectroscopy was 1.7 ppm.

    DOI: 10.1088/1538-3873/ab42f1

    Web of Science

    arXiv

  18. OGLE-2015-BLG-1649Lb: A gas giant planet around a low-mass dwarf 査読有り

    Nagakane M., Lee C.H., Koshimoto N., Suzuki D., Udalski A., Beaulieu J.P., Sumi T., Bennett D.P., Bond I.A., Rattenbury N., Bachelet E., Dominik M., Abe F., Barry R.K., Bhattacharya A., Donachie M., Fujii H., Fukui A., Hirao Y., Itow Y., Kamei Y., Kondo I., Li M.C.A., Matsubara Y., Matsuo T., Miyazaki S., Muraki Y., Ranc C., Shibai H., Suematsu H., Sullivan D.J., Tristram P.J., Yamakawa T., Yonehara A., Mróz P., Poleski R., Skowron J., Szymański M.K., Soszyński I., Pietrukowicz P., Kozłowski S., Ulaczyk K., Bramich D.M., Cassan A., Jaimes R.F., Horne K., Hundertmark M., Mao S., Menzies J., Schmidt R., Snodgrass C., Steele I.A., Street R., Tsapras Y., Wambsganss J., Jørgensen U.G., Bozza V., Longã P., Peixinho N., Skottfelt J., Southworth J., Andersen M.I., Burgdorf M.J., D’Ago G., Evans D.F., Hinse T.C., Korhonen H., Rabus M., Rahvar S.

    Astronomical Journal   158 巻 ( 5 )   2019年11月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Astronomical Journal  

    We report the discovery of an exoplanet from the analysis of the gravitational microlensing event OGLE-2015BLG-1649 that challenges the core accretion model of planet formation and appears to support the disk instability model. The planet/host-star mass ratio is q = 7.2 × 10−3 and the projected separation normalized to the angular Einstein radius is s = 0.9. We conducted high-resolution follow-up observations using the Infrared Camera and Spectrograph (IRCS) camera on the Subaru telescope and are able to place an upper limit on the lens flux. From these measurements we are able to exclude all host stars greater than or equal in mass to a G-type dwarf. We conducted a Bayesian analysis with these new flux constraints included as priors resulting in estimates of the masses of the host star and planet. These are ML = 0.34 ± 0.19 M☉ and Mp = 2.5-1.4+1.5 MJup, respectively. The distance to the system is DL = 4.23-1.64+1.51 kpc. The projected star–planet separation is a⊥ = 2.07-0.77+0.65 au. The estimated relative lens-source proper motion, ∼7.1 mas yr−1, is fairly high and thus the lens can be better constrained if additional follow-up observations are conducted several years after the event.

    DOI: 10.3847/1538-3881/ab4881

    Web of Science

    Scopus

    arXiv

  19. Multiple Populations of Extrasolar Gas Giants 査読有り

    Shohei Goda, Taro Matsuo

    ASTROPHYSICAL JOURNAL   876 巻 ( 1 )   2019年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IOP PUBLISHING LTD  

    There are two planetary formation scenarios: core accretion and gravitational disk instability. Based on the fact that gaseous objects are preferentially observed around metal-rich host stars, most extrasolar gaseous objects discovered to date are thought to have been formed by core accretion. Here, we present 569 samples of gaseous planets and brown dwarfs found in 485 planetary systems that span three mass regimes with boundary values at 4 and 25 Jupiter-mass masses through performing cluster analyses of these samples regarding the host-star metallicity, after minimizing the impact of the selection effect of radial-velocity measurement on the cluster analysis. The larger mass is thought to be the upper mass limit of the objects that were formed during the planetary formation processes. In contrast, the lower mass limit appears to reflect the difference between planetary formation processes around early-type and G-type stars; disk instability plays a greater role in the planetary formation process around early-type stars than that around G-type stars. Populations with masses between 4 and 25 Jupiter masses that orbit early-type stars comprise planets formed not only via the core-accretion process but also via gravitational disk instability because the population preferentially orbits metal-poor stars or is independent of the host-star metallicity. Therefore, it is essential to have a hybrid scenario for the planetary formation of the diverse systems.

    DOI: 10.3847/1538-4357/ab0f9c

    Web of Science

    arXiv

  20. Multi-epoch Direct Imaging and Time-variable Scattered Light Morphology of the HD 163296 Protoplanetary Disk 査読有り

    Evan A. Rich, John P. Wisniewski, Thayne Currie, Misato Fukagawa, Carol A. Grady, Michael L. Sitko, Monika Pikhartova, Jun Hashimoto, Lyu Abe, Wolfgang Brandner, Timothy D. Brandt, Joseph C. Carson, Jeffrey Chilcote, Ruobing Dong, Markus Feldt, Miwa Goto, Tyler Groff, Olivier Guyon, Yutaka Hayano, Masahiko Hayashi, Saeko S. Hayashi, Thomas Henning, Klaus W. Hodapp, Miki Ishii, Masanori Iye, Markus Janson, Nemanja Jovanovic, Ryo Kandori, Jeremy Kasdin, Gillian R. Knapp, Tomoyuki Kudo, Nobuhiko Kusakabe, Masayuki Kuzuhara, Jungmi Kwon, Julien Lozi, Frantz Martinache, Taro Matsuo, Satoshi Mayama, Michael W. McElwain, Shoken Miyama, Jun-Ichi Morino, Amaya Moro-Martin, Takao Nakagawa, Tetsuo Nishimura, Tae-Soo Pyo, Eugene Serabyn, Hiroshi Suto, Ray W. Russel, Ryuji Suzuki, Michihiro Takami, Naruhisa Takato, Hiroshi Terada, Christian Thalmann, Edwin L. Turner, Taichi Uyama, Kevin R. Wagner, Makoto Watanabe, Toru Yamada, Hideki Takami, Tomonori Usuda, Motohide Tamura

    ASTROPHYSICAL JOURNAL   875 巻 ( 1 )   2019年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IOP PUBLISHING LTD  

    We present H-band polarized scattered light imagery and JHK high-contrast spectroscopy of the protoplanetary disk around HD 163296 observed with the High-Contrast Coronographic Imager for Adaptive Optics (HiCIAO) and Subaru Coronagraphic Extreme Adaptive Optics (SCExAO)/Coronagraphic High Angular Resolution Imaging Spectrograph (CHARTS) instruments at Subaru Observatory. The polarimetric imagery resolve a broken ring structure surrounding HD 163296 that peaks at a distance along the major axis of 0 ''.65 (66 au) and extends out to 0 ''.98 (100 au) along the major axis. Our 2011 H-band data exhibit clear axisymmetry, with the NW and SE side of the disk exhibiting similar intensities. Our data are clearly different from 2016 epoch H-band observations of the Very Large Telescope (VLT)/Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE), which found a strong 2.7 x asymmetry between the NW and SE side of the disk. Collectively, these results indicate the presence of time-variable, non-azimuthally symmetric illumination of the outer disk. While our SCExAO/CHARIS data are sensitive enough to recover the planet candidate identified from NIRC2 in the thermal infrared (IR), we fail to detect an object with JHK brightness nominally consistent with this object. This suggests that the candidate is either fainter in JHK bands than model predictions, possibly due to extinction from the disk or atmospheric dust/clouds, or that it is an artifact of the data set/data processing, such as a residual speckle or partially subtracted disk feature. Assuming standard hot-start evolutionary models and a system age of 5 Myr, we set new, direct mass limits for the inner (outer) Atacama Large Millimeter/submillimeter Array (ALMA)-predicted protoplanet candidate along the major (minor) disk axis of of 1.5 (2) M-J.

    DOI: 10.3847/1538-4357/ab0f3b

    Web of Science

    arXiv

  21. MOA-bin-29b: A microlensing gas-giant planet orbiting a low-mass host star 査読有り

    Kondo I., Sumi T., Bennett D.P., Udalski A., Bond I.A., Rattenbury N.J., Bozza V., Hirao Y., Suzuki D., Koshimoto N., Nagakane M., Miyazaki S., Abe F., Barry R., Bhattacharya A., Donachie M., Fukui A., Fujii H., Itow Y., Kamei Y., Li M.C.A., Matsubara Y., Matsuo T., Muraki Y., Ranc C., Shibai H., Suematsu H., Sullivan D.J., Tristram P.J., Yamakawa T., Yonehara A., Mróz P., Szymanski M.K., Soszynski I., Ulaczyk K.

    Astronomical Journal   158 巻 ( 6 )   2019年

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Astronomical Journal  

    We report the discovery of a gas-giant planet orbiting a low-mass host star in the microlensing event MOA-bin-29 that occurred in 2006. We find five degenerate solutions with the planet/host-star mass ratio of q~10-2. The Einstein radius crossing time of all models are relatively short (~4-7 days), which indicates that the mass of host star is likely low. The measured lens-source proper motion is 5-9 mas yr-1depending on the models. Since only finite source effects are detected, we conduct a Bayesian analysis in order to obtain the posterior probability distribution of the lens physical properties. As a result, we find the lens system is likely to be a gas-giant orbiting a brown dwarf or a very late M-dwarf in the Galactic bulge. The probability distributions of the physical parameters for the five degenerate models are consistent within the range of error. By combining these probability distributions, we conclude that the lens system is a gas giant with a mass of Mp= 0.63+1.13-0.39MJuporbiting a brown dwarf with a mass of Mh= 0.06+0.11-0.04Modot;at a projected star-planet separation of r = 0.53+0.89-0.18au. The lens distance is DL= 6.89+1.19-1.19kpc, i.e., likely within the Galactic bulge.

    DOI: 10.3847/1538-3881/AB4E9E

    Web of Science

    Scopus

    arXiv

  22. A New Method for Calibration of Gain Variation in a Detector System 査読有り

    Shohei Goda, Taro Matsuo

    ASTRONOMICAL JOURNAL   156 巻 ( 6 )   2018年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IOP PUBLISHING LTD  

    Transit spectroscopy of habitable planets orbiting late-type stars requires high relative spectrophotometric accuracy between wavelengths during transit/eclipse observation. The spectrophotometric signal is affected not only by image movement and deformation due to wavefront error but also by electrical variation in the detector system. These time-variation components, coupled to the transit signal, distort the measurements of atmospheric composition in transit spectroscopy. Here we propose a new concept for improvement of spectrophotometric accuracy through the calibration of the time-variation components in the detector system by developing densified pupil spectroscopy that provides multiple spectra of the star-planet system. Owing to a group of pixels exposed by the object light (i.e., science pixels), pixel-to-pixel variations can be smoothed out through an averaging operation; thus, only common time-variation components over the science pixels remain. In addition, considering that the detector plane is optically conjugated to the pupil plane, a pupil mask can completely block astronomical light coming into residual pixels. The common time-variation components are reconstructed with the residual pixels and reduced into a random term. Applying the densified pupil spectrograph with a mid-infrared detector system to a large space cryogenic telescope such as the Origins Space Telescope, we show that the system nearly achieves photon noise-limited performance and detects absorption features through transmission spectroscopy and secondary eclipse of terrestrial planets orbiting M-type stars at 10 pc with 60 transit observations. Thus, the proposed method contributes to the measurement of planetary habitability and biosignatures of the nearby transiting habitable candidates.

    DOI: 10.3847/1538-3881/aaeb29

    Web of Science

    arXiv

  23. A chemical survey of exoplanets with ARIEL 査読有り

    Giovanna Tinetti, Pierre Drossart, Paul Eccleston, Paul Hartogh, Astrid Heske, Jeremy Leconte, Giusi Micela, Marc Ollivier, Goran Pilbratt, Ludovic Puig, Diego Turrini, Bart Vandenbussche, Paulina Wolkenberg, Jean-Philippe Beaulieu, Lars A. Buchave, Martin Ferus, Matt Griffin, Manuel Guedel, Kay Justtanont, Pierre-Olivier Lagage, Pedro Machado, Giuseppe Malaguti, Michiel Min, Hans Ulrik Norgaard-Nielsen, Mirek Rataj, Tom Ray, Ignasi Ribas, Mark Swain, Robert Szabo, Stephanie Werner, Joanna Barstow, Matt Burleigh, James Cho, Vincent Coude du Foresto, Athena Coustenis, Leen Decin, Therese Encrenaz, Marina Galand, Michael Gillon, Ravit Helled, Juan Carlos Morales, Antonio Garcia Munoz, Andrea Moneti, Isabella Pagano, Enzo Pascale, Giuseppe Piccioni, David Pinfield, Subhajit Sarkar, Franck Selsis, Jonathan Tennyson, Amaury Triaud, Olivia Venot, Ingo Waldmann, David Waltham, Gillian Wright, Jerome Amiaux, Jean-Louis Augueres, Michel Berthe, Naidu Bezawada, Georgia Bishop, Neil Bowles, Deirdre Coffey, Josep Colome, Martin Crook, Pierre-Elie Crouzet, Vania Da Peppo, Isabel Escudero Sanz, Mauro Focardi, Martin Frericks, Tom Hunt, Ralf Kohley, Kevin Middleton, Gianluca Morgante, Roland Ottensamer, Emanuele Pace, Chris Pearson, Richard Stamper, Kate Symonds, Miriam Rengel, Etienne Renotte, Peter Ade, Laura Affer, Christophe Alard, Nicole Allard, Francesca Altieri, Yves Andre, Claudio Arena, Ioannis Argyriou, Alan Aylward, Cristian Baccani, Gaspar Bakos, Marek Banaszkiewicz, Mike Barlow, Virginie Batista, Giancarlo Bellucci, Serena Benatti, Pernelle Bernardi, Bruno Bezard, Maria Blecka, Emeline Bolmont, Bertrand Bonfond, Rosaria Bonito, Aldo S. Bonomo, John Robert Brucato, Allan Sacha Brun, Ian Bryson, Waldemar Bujwan, Sarah Casewell, Bejamin Charnay, Cesare Cecchi Pestellini, Guo Chen, Angela Ciaravella, Riccardo Claudi, Rodolphe Cledassou, Mario Damasso, Mario Damiano, Camilla Danielski, Pieter Deroo, Anna Maria Di Giorgio, Carsten Dominik, Vanessa Doublier, Simon Doyle, Rene Doyon, Benjamin Drummond, Bastien Duong, Stephen Eales, Billy Edwards, Maria Farina, Ettore Flaccomio, Leigh Fletcher, Francois Forget, Steve Fossey, Markus Fraenz, Yuka Fujii, Alvaro Garcia-Piquer, Walter Gear, Herve Geoffray, Jean Claude Gerard, Lluis Gesa, H. Gomez, Rafal Graczyk, Caitlin Griffith, Denis Grodent, Mario Giuseppe Guarcello, Jacques Gustin, Keiko Hamano, Peter Hargrave, Yann Hello, Kevin Heng, Enrique Herrero, Allan Hornstrup, Benoit Hubert, Shigeru Ida, Masahiro Ikoma, Nicolas Iro, Patrick Irwin, Christopher Jarchow, Jean Jaubert, Hugh Jones, Queyrel Julien, Shingo Kameda, Franz Kerschbaum, Pierre Kervella, Tommi Koskinen, Matthijs Krijger, Norbert Krupp, Marina Lafarga, Federico Landini, Emanuel Lellouch, Giuseppe Leto, A. Luntzer, Theresa Rank-Luftinger, Antonio Maggio, Jesus Maldonado, Jean-Pierre Maillard, Urs Mall, Jean-Baptiste Marquette, Stephane Mathis, Pierre Maxted, Taro Matsuo, Alexander Medvedev, Yamila Miguel, Vincent Minier, Giuseppe Morello, Alessandro Mura, Norio Narita, Valerio Nascimbeni, N. Nguyen Tong, Vladimiro Noce, Fabrizio Oliva, Enric Palle, Paul Palmer, Maurizio Pancrazzi, Andreas Papageorgiou, Vivien Parmentier, Manuel Perger, Antonino Petralia, Stefano Pezzuto, Ray Pierrehumbert, Ignazio Pillitteri, Giampaolo Piotto, Giampaolo Pisano, Loredana Prisinzano, Aikaterini Radioti, Jean-Michel Reess, Ladislav Rezac, Marco Rocchetto, Albert Rosich, Nicoletta Sanna, Alexandre Santerne, Giorgio Savini, Gaetano Scandariato, Bruno Sicardy, Carles Sierra, Giuseppe Sindoni, Konrad Skup, Ignas Snellen, Mateusz Sobiecki, Lauriane Soret, Alessandro Sozzetti, A. Stiepen, Antoine Strugarek, Jake Taylor, William Taylor, Luca Terenzi, Marcell Tessenyi, Angelos Tsiaras, C. Tucker, Diana Valencia, Gautam Vasisht, Allona Vazan, Francesc Vilardell, Sabrine Vinatier, Serena Viti, Rens Waters, Piotr Wawer, Anna Wawrzaszek, Anthony Whitworth, Yuk L. Yung, Sergey N. Yurchenko, Maria Rosa Zapatero Osorio, Robert Zellem, Tiziano Zingales, Frans Zwart

    EXPERIMENTAL ASTRONOMY   46 巻 ( 1 ) 頁: 135 - 209   2018年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER  

    Thousands of exoplanets have now been discovered with a huge range of masses, sizes and orbits: from rocky Earth-like planets to large gas giants grazing the surface of their host star. However, the essential nature of these exoplanets remains largely mysterious: there is no known, discernible pattern linking the presence, size, or orbital parameters of a planet to the nature of its parent star. We have little idea whether the chemistry of a planet is linked to its formation environment, or whether the type of host star drives the physics and chemistry of the planet's birth, and evolution. ARIEL was conceived to observe a large number (1000) of transiting planets for statistical understanding, including gas giants, Neptunes, super-Earths and Earth-size planets around a range of host star types using transit spectroscopy in the 1.25-7.8m spectral range and multiple narrow-band photometry in the optical. ARIEL will focus on warm and hot planets to take advantage of their well-mixed atmospheres which should show minimal condensation and sequestration of high-Z materials compared to their colder Solar System siblings. Said warm and hot atmospheres are expected to be more representative of the planetary bulk composition. Observations of these warm/hot exoplanets, and in particular of their elemental composition (especially C, O, N, S, Si), will allow the understanding of the early stages of planetary and atmospheric formation during the nebular phase and the following few million years. ARIEL will thus provide a representative picture of the chemical nature of the exoplanets and relate this directly to the type and chemical environment of the host star. ARIEL is designed as a dedicated survey mission for combined-light spectroscopy, capable of observing a large and well-defined planet sample within its 4-year mission lifetime. Transit, eclipse and phase-curve spectroscopy methods, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allow us to measure atmospheric signals from the planet at levels of 10-100 part per million (ppm) relative to the star and, given the bright nature of targets, also allows more sophisticated techniques, such as eclipse mapping, to give a deeper insight into the nature of the atmosphere. These types of observations require a stable payload and satellite platform with broad, instantaneous wavelength coverage to detect many molecular species, probe the thermal structure, identify clouds and monitor the stellar activity. The wavelength range proposed covers all the expected major atmospheric gases from e.g. H2O, CO2, CH4 NH3, HCN, H2S through to the more exotic metallic compounds, such as TiO, VO, and condensed species. Simulations of ARIEL performance in conducting exoplanet surveys have been performed - using conservative estimates of mission performance and a full model of all significant noise sources in the measurement - using a list of potential ARIEL targets that incorporates the latest available exoplanet statistics. The conclusion at the end of the Phase A study, is that ARIEL - in line with the stated mission objectives - will be able to observe about 1000 exoplanets depending on the details of the adopted survey strategy, thus confirming the feasibility of the main science objectives.

    DOI: 10.1007/s10686-018-9598-x

    Web of Science

  24. MOA-2015-BLG-337: A Planetary System with a Low-mass Brown Dwarf/Planetary Boundary Host, or a Brown Dwarf Binary 査読有り

    Miyazaki S., Sumi T., Bennett D.P., Gould A., Udalski A., Bond I.A., Koshimoto N., Nagakane M., Rattenbury N., Abe F., Bhattacharya A., Barry R., Donachie M., Fukui A., Hirao Y., Itow Y., Kawasaki K., Li M.C.A., Ling C.H., Matsubara Y., Matsuo T., Muraki Y., Ohnishi K., Ranc C., Saito T., Sharan A., Shibai H., Suematsu H., Suzuki D., Sullivan D.J., Tristram P.J., Yamada T., Yonehara A., KozŁowski S., Mróz P., Pawlak M., Poleski R., Pietrukowicz P., Skowron J., Soszyński I., Szymański M.K., Ulaczyk K., Albrow M.D., Chung S.J., Han C., Jung Y.K., Hwang K.H., Ryu Y.H., Shin I.G., Shvartzvald Y., Yee J.C., Zang W., Zhu W., Cha S.M., Kim D.J., Kim H.W., Kim S.L., Lee C.U., Lee D.J., Lee Y., Park B.G., Pogge R.W.

    Astronomical Journal   156 巻 ( 3 )   2018年9月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Astronomical Journal  

    We report on the discovery and analysis of the short-timescale binary-lens microlensing event, MOA-2015-BLG-337. The lens system could be a planetary system with a very low-mass host, around the brown dwarf (BD)/planetary-mass boundary, or a BD binary. We found two competing models that explain the observed light curves with companion/host mass ratios of q ∼ 0.01 and ∼0.17, respectively. A significant finite source effect in the best-fit planetary model (q ∼ 0.01) reveals a small angular Einstein radius of θ E ≃ 0.03 mas, which favors a low-mass lens. We obtain the posterior probability distribution of the lens properties from a Bayesian analysis. The results for the planetary models strongly depend on a power-law index in planetary-mass regime, pl, in the assumed mass function. In summary, there are two solutions of the lens system: (1) a BD/planetary-mass boundary object orbited by a super-Neptune (the planetary model with α pl = 0.49) and (2) a BD binary (the binary model). If the planetary models are correct, this system can be one of a new class of planetary system, having a low host mass and also a planetary-mass ratio (q < 0.03) between the companion and its host. The discovery of the event is important for the study of planetary formation in very low-mass objects. In addition, it is important to consider all viable solutions in these kinds of ambiguous events in order for the future comprehensive statistical analyses of planetary/binary microlensing events.

    DOI: 10.3847/1538-3881/aad5ee

    Web of Science

    Scopus

  25. Subaru/HiCIAO HKs Imaging of LKHa 330: Multi-band Detection of the Gap and Spiral-like Structures 査読有り

    Taichi Uyama, Jun Hashimoto, Takayuki Muto, Eiji Akiyama, Ruobing Dong, Jerome de Leon, Itsuki Sakon, Tomoyuki Kudo, Nobuhiko Kusakabe, Masayuki Kuzuhara, Mickael Bonnefoy, Lyu Abe, Wolfgang Brandner, Timothy D. Brandt, Joseph C. Carson, Thayne Currie, Sebastian Egner, Markus Feldt, Jeffrey Fung, Miwa Goto, Carol A. Grady, Olivier Guyon, Yutaka Hayano, Masahiko Hayashi, Saeko S. Hayashi, Thomas Henning, Klaus W. Hodapp, Miki Ishii, Masanori Iye, Markus Janson, Ryo Kandori, Gillian R. Knapp, Jungmi Kwon, Taro Matsuo, Satoshi Mayama, Michael W. Mcelwain, Shoken Miyama, Jun-Ichi Morino, Amaya Moro-Martin, Tetsuo Nishimura, Tae-Soo Pyo, Eugene Serabyn, Michael L. Sitko, Takuya Suenaga, Hiroshi Suto, Ryuji Suzuki, Yasuhiro H. Takahashi, Michihiro Takami, Naruhisa Takato, Hiroshi Terada, Christian Thalmann, Edwin L. Turner, Makoto Watanabe, John Wisniewski, Toru Yamada, Yi Yang, Hideki Takami, Tomonori Usuda, Motohide Tamura

    ASTRONOMICAL JOURNAL   156 巻 ( 2 )   2018年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IOP PUBLISHING LTD  

    We present H- and K-s-bands observations of the LkH alpha 330 disk with a multi-band detection of the large gap and spiral-like structures. The morphology of the outer disk (r similar to 0."3) at PA = 0 degrees-45 degrees and PA degrees = 180-290 degrees is likely density wave-induced spirals, and comparison between our observational results and simulations suggests a planet formation. We have also investigated the azimuthal profiles at the ring and the outer-disk regions as well as radial profiles in the directions of the spiral-like structures and semimajor axis. Azimuthal analysis shows a large variety in wavelength and implies that the disk has non-axisymmetric dust distributions. The radial profiles in the major-axis direction (PA = 271 degrees) suggest that the outer region (r >= 0."25) may be influenced by shadows of the inner region of the disk. The spiral-like directions (PA = 10 degrees and 230 degrees) show different radial profiles, which suggests that the surfaces of the spiral-like structures are highly flared and/or have different dust properties. Finally, a color map of the disk shows a lack of an outer eastern region in the H-band disk, which may hint at the presence of an inner object that casts a directional shadow onto the disk.

    DOI: 10.3847/1538-3881/aacbd1

    Web of Science

    arXiv

  26. High-contrast Polarimetry Observation of the T Tau Circumstellar Environment 査読有り

    Yi Yang, Satoshi Mayama, Saeko S. Hayashi, Jun Hashimoto, Roman Rafikov, Eiji Akiyama, Thayne Currie, Markus Janson, Munetake Momose, Takao Nakagawa, Daehyeon Oh, Tomoyuki Kudo, Nobuhiko Kusakabe, Lyu Abe, Wolfgang Brandner, Timothy D. Brandt, Joseph C. Carson, Sebastian Egner, Markus Feldt, Miwa Goto, Carol A. Grady, Olivier Guyon, Yutaka Hayano, Masahiko Hayashi, Thomas Henning, Klaus W. Hodapp, Miki Ishii, Masanori Iye, Ryo Kandori, Gillian R. Knapp, Jungmi Kwon, Masayuki Kuzuhara, Taro Matsuo, Michael W. Mcelwain, Shoken Miyama, Jun-Ichi Morino, Amaya Moro-martin, Tetsuo Nishimura, Tae-Soo Pyo, Eugene Serabyn, Takuya Suenaga, Hiroshi Suto, Ryuji Suzuki, Yasuhiro H. Takahashi, Michihiro Takami, Naruhisa Takato, Hiroshi Terada, Christian Thalmann, Edwin L. Turner, Makoto Watanabe, John Wisniewski, Toru Yamada, Hideki Takami, Tomonori Usuda, Motohide Tamura

    ASTROPHYSICAL JOURNAL   861 巻 ( 2 )   2018年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IOP PUBLISHING LTD  

    We conducted high-contrast polarimetry observations of T Tau in the H-band, using the High Contrast Instrument for the Subaru Next Generation Adaptive Optics instrument mounted on the Subaru Telescope, revealing structures as near as 0 1 from the stars T Tau N and T Tau S. The whole T Tau system is found to be surrounded by nebulalike envelopes, and several outflow-related structures are detected in these envelopes. We analyzed the detailed polarization patterns of the circumstellar structures near each component of this triple young star system and determined constraints on the circumstellar disks and outflow structures. We suggest that the nearly face-on circumstellar disk of T Tau N is no larger than 0.''8, or 117 au, in the northwest, based on the existence of a hole in this direction, and no larger than 0.''27, or 40 au, in the south. A new structure, "N5," extends to about 0.''42, or 59 au, southwest of the star, and is believed to be part of the disk. We suggest that T Tau S is surrounded by a highly inclined circumbinary disk with a radius of about 0.''3, or 44 au, with a position angle of about 30 degrees, that is misaligned with the orbit of the T Tau S binary. After analyzing the positions and polarization vector patterns of the outflow-related structures, we suggest that T Tau S should trigger the well-known E-W outflow, and is also likely to be responsible for a southwest precessing outflow "coil" and a possible south outflow.

    DOI: 10.3847/1538-4357/aac6c8

    Web of Science

    arXiv

  27. The infrared Doppler (IRD) instrument for the Subaru telescope: instrument description and commissioning results 査読有り

    Takayuki Kotani, Motohide Tamura, Jun Nishikawa, Akitoshi Ueda, Masayuki Kuzuhara, Masashi Omiya, Jun Hashimoto, Masato Ishizuka, Teruyuki Hirano, Hiroshi Suto, Takashi Kurokawa, Tsukasa Kokubo, Takahiro Mori, Yosuke Tanaka, Ken Kashiwagi, Mihoko Konishi, Tomoyuki Kudo, Bun'ei Sato, Shane Jacobson, Klaus W. Hodapp, Donald B. Hall, Wako Aoki, Tomonori Usuda, Shogo Nishiyama, Tadashi Nakajima, Yuji Ikeda, Tomoyasu Yamamuro, Jun-Ichi Morino, Haruka Baba, Ko Hosokawa, Hiroyuki Tako Ishikawa, Norio Narita, Eiichiro Kokubo, Yutaka Hayano, Hideyuki Izumiura, Eiji Kambe, Nobuhiko Kusakabe, Jungmi Kwon, Masahiro Ikoma, Yasunori Hori, Hidenori Genda, Akihiko Fukui, Yuka Fujii, Hajime Kawahara, Olivier Guyon, Nemanja Jovanovi, Hiroki Harakawa, Masahiko Hayashi, Masahide Hidai, Masahiro Machida, Taro Matsuo, Tetsuya Nagata, Masahiro Ogihara, Hideki Takami, Naruhisa Takato, Hiroshi Terada, Daehyeon Oh

    GROUND-BASED AND AIRBORNE INSTRUMENTATION FOR ASTRONOMY VII   10702 巻   2018年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    The Infrared Doppler (IRD) instrument is a fiber-fed high-resolution NIR spectrometer for the Subaru telescope covering the Y,J,H-bands simultaneously with a maximum spectral resolution of 70,000. The main purpose of IRD is a search for Earth-mass planets around nearby M-dwarfs by precise radial velocity measurements, as well as a spectroscopic characterization of exoplanet atmospheres. We report the current status of the instrument, which is undergoing commissioning at the Subaru Telescope, and the first light observation successfully done in August 2017. The general description of the instrument will be given including spectrometer optics, fiber injection system, cryogenic system, scrambler, and laser frequency comb. A large strategic survey mainly focused on late-type M-dwarfs is planned to start from 2019.

    DOI: 10.1117/12.2311836

    Web of Science

  28. Mid-Infrared Imager, Spectrometer, Coronagraph (MISC) for the Origins Space Telescope (OST) 査読有り

    Itsuki Sakon, Thomas L. Roellig, Kimberly Ennico-Smith, Taro Matsuo, Yuji Ikeda, Tomoyasu Yamamuro, Naofumi Fujishiro, Keigo Enyag, Aoi Takahashi, Takehiko Wada, Olivier Guyon, Takayuki Kotani, Jun Nishikawa, Naoshi Murakami, Yuki Sarugaku, Denis Burgarella

    SPACE TELESCOPES AND INSTRUMENTATION 2018: OPTICAL, INFRARED, AND MILLIMETER WAVE   10698 巻   2018年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    The Mid-infrared Imager, Spectrometer, Coronagraph (MISC) is one of the instruments studied both for the Origins Space Telescope (OST) Mission Concept 1 and 2. The highest ever spectro-photometric stability achieved by MISC transit spectrometer module (MISC TRA) enables to detect bio-signatures (e.g., ozone, water, and methane) in habitable worlds in both primary and secondary transits of exoplanets and makes the OST a powerful tool to bring a revolutionary progress in exoplanet sciences. Combined with the spectroscopic capability in the FIR provided by other OST instruments, the MISC widens the wavelength coverage of OST down to 4 mu m, which makes the OST a powerful tool to diagnose the physical and chemical condition of the ISM using dust features, molecules lines and atomic and ionic lines. The MISC also provides the OST with a focal plane guiding function for the other OST science instruments as well as its own use.

    DOI: 10.1117/12.2314177

    Web of Science

  29. A highly stable spectrophotometric capability for the Origins Space Telescope (OST) Mid-infrared Imager, Spectrometer, Coronagraph (MISC) 査読有り

    Taro Matsuo, Thomas Greene, Thomas L. Roellig, Robert E. McMurray, Roy R. Johnson, Ali Kashani, Shohei Goda, Masayuki Ido, Satoshi Ito, Takahiro Tsuboi, Tomoyasu Yamamuro, Yuji Ikeda, Hiroshi Shibai, Takahiro Sumi, Itsuki Sakon, Kimberly Ennico-Smith

    SPACE TELESCOPES AND INSTRUMENTATION 2018: OPTICAL, INFRARED, AND MILLIMETER WAVE   10698 巻   2018年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    This paper describes the transit spectrograph designed for the Origins Space Telescope mid-infrared imager, spectrometer, coronagraph (MISC) and its performance derived through analytical formulation and numerical simulation. The transit spectrograph is designed based on a densified pupil spectroscopy design that forms multiple independent spectra on the detector plane and minimizes the systematic noise in the optical system. This design can also block any thermal light incoming into pixels around the transit spectra. The gain fluctuations occurring in the detector and readout electronics are accurately corrected by use of a number of blanked-off pixels. We found that the transit spectrograph for the OST concept 1 with a diameter of 9.3m potentially achieves the photon-noise-limited performance and allows detection of biosignature gases through transmission spectroscopy of transiting planets orbiting late- and middle-M type stars at 10 pc with 60 transit observations.

    DOI: 10.1117/12.2311896

    Web of Science

  30. The fundamental stellar parameters of FGK stars in the SEEDS survey Norman, OK 73071, USA 査読有り

    Evan A. Rich, John P. Wisniewski, Michael W. McElwain, Jun Hashimoto, Tomoyuki Kudo, Nobuhiko Kusakabe, Yoshiko K. Okamoto, Lyu Abe, Eiji Akiyama, Wolfgang Brandner, Timothy D. Brandt, Phillip Cargile, Joseph C. Carson, Thayne M. Currie, Sebastian Egner, Markus Feldt, Misato Fukagawa, Miwa Goto, Carol A. Grady, Olivier Guyon, Yutaka Hayano, Masahiko Hayashi, Saeko S. Hayashi, Leslie Hebb, Krzysztof G. Helminiak, Thomas Henning, Klaus W. Hodapp, Miki Ishii, Masanori Iye, Markus Janson, Ryo Kandori, Gillian R. Knapp, Masayuki Kuzuhara, Jungmi Kwon, Taro Matsuo, Satoshi Mayama, Shoken Miyama, Munetake Momose, Jun-Ichi Morino, Amaya Moro-Martin, Takao Nakagawa, Tetsuo Nishimura, Daehyeon Oh, Tae-Soo Pyo, Joshua Schlieder, Eugene Serabyn, Michael L. Sitko, Takuya Suenaga, Hiroshi Suto, Ryuji Suzuki, Yasuhiro H. Takahashi, Michihiro Takami, Naruhisa Takato, Hiroshi Terada, Christian Thalmann, Daigo Tomono, Edwin L. Turner, Makoto Watanabe, Toru Yamada, Hideki Takami, Tomonori Usuda, Motohide Tamura

    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY   472 巻 ( 2 ) 頁: 1736 - 1752   2017年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:OXFORD UNIV PRESS  

    Large exoplanet surveys have successfully detected thousands of exoplanets to-date. Utilizing these detections and non-detections to constrain our understanding of the formation and evolution of planetary systems also requires a detailed understanding of the basic properties of their host stars. We have determined the basic stellar properties of F, K and G stars in the Strategic Exploration of Exoplanets and Disks with Subaru (SEEDS) survey from Echelle spectra taken at the Apache Point Observatory's 3.5m telescope. Using ROBOSPECT to extract line equivalent widths and TemperatureGravity microtrubulentVelocity ITerations to calculate the fundamental parameters, we have computed T-eff, log(g), v(t), [Fe/H], chromospheric activity and the age for our sample. Our methodology was calibrated against previously published results for a portion of our sample. The distribution of [Fe/H] in our sample is consistent with that typical of the Solar neighbourhood. Additionally, we find the ages of most of our sample are < 500 Myr, but note that we cannot determine robust ages from significantly older stars via chromospheric activity age indicators. The futuremeta-analysis of the frequency ofwide stellar and sub-stellar companions imaged via the SEEDS survey will utilize our results to constrain the occurrence of detected comoving companions with the properties of their host stars.

    DOI: 10.1093/mnras/stx2051

    Web of Science

    arXiv

  31. Pupil Masks for Spectrophotometry of Transiting Exoplanets 査読有り

    Satoshi Itoh, Taro Matsuo, Shohei Goda, Hiroshi Shibai, Takahiro Sumi

    ASTRONOMICAL JOURNAL   154 巻 ( 3 )   2017年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IOP PUBLISHING LTD  

    Spectrophotometric stability, which is crucial in the spectral characterization of transiting exoplanets, is affected by photometric variations arising from field-stop loss in space telescopes with pointing jitter or primary mirror deformation. This paper focuses on a new method for removing slit-loss or field-stop-loss photometric variation through the use of a pupil mask. Two types of pupil function are introduced: the first uses conventional (e.g., Gaussian or hyper-Gaussian) apodizing patterns; whereas the second, which we call a block-shaped mask, employs a new type of pupil mask designed for high photometric stability. A methodology for the optimization of a pupil mask for transit observations is also developed. The block-shaped mask can achieve a photometric stability of 10(-5) for a nearly arbitrary field-stop radius when the pointing jitter is smaller than approximately 0.7 lambda/D and a photometric stability of 10(-6) at a pointing jitter smaller than approximately 0.5 lambda/D. The impact of optical aberrations and mask imperfections upon mask performance is also discussed.

    DOI: 10.3847/1538-3881/aa8304

    Web of Science

    arXiv

  32. OGLE-2013-BLG-1761Lb: A Massive Planet around an M/K Dwarf 査読有り

    Hirao Y., Udalski A., Sumi T., Bennett D.P., Koshimoto N., Bond I.A., Rattenbury N.J., Suzuki D., Abe F., Asakura Y., Barry R.K., Bhattacharya A., Donachie M., Evans P., Fukui A., Itow Y., Li M.C.A., Ling C.H., Masuda K., Matsubara Y., Matsuo T., Muraki Y., Nagakane M., Ohnishi K., Ranc C., Saito T., Sharan A., Shibai H., Sullivan D.J., Tristram P.J., Yamada T., Yamada T., Yonehara A., Poleski R., Skowron J., Mróz P., Szymański M.K., Kozłowski S., Pietrukowicz P., Soszyński I., Wyrzykowski , Ulaczyk K.

    Astronomical Journal   154 巻 ( 1 )   2017年7月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Astronomical Journal  

    We report the discovery and the analysis of the planetary microlensing event, OGLE-2013-BLG-1761. There are some degenerate solutions in this event because the planetary anomaly is only sparsely sampled. However, the detailed light-curve analysis ruled out all stellar binary models and shows the lens to be a planetary system. There is the so-called close/wide degeneracy in the solutions with the planet/host mass ratio of q ∼ (7.0 ±2.0) ×10-3 and q ∼ (8.1 ±2.6) ×10-3 with the projected separation in Einstein radius units of s = 0.95 (close) and s = 1.18 (wide), respectively. The microlens parallax effect is not detected, but the finite source effect is detected. Our Bayesian analysis indicates that the lens system is located DL = 6.9+1.0-1.2. away from us and the host star is an M/K dwarf with a mass of ML = 0.33+0.32-0.19 M⊙ orbited by a super-Jupiter mass planet with a mass of mp = 2.7+2.5-1.5 MJup at the projected separation of a⊥ = 1.8+0.5-0.5 au. The preference of the large lens distance in the Bayesian analysis is due to the relatively large observed source star radius. The distance and other physical parameters may be constrained by the future high-resolution imaging by large ground telescopes or HST. If the estimated lens distance is correct, then this planet provides another sample for testing the claimed deficit of planets in the Galactic bulge.

    DOI: 10.3847/1538-3881/aa73da

    Web of Science

    Scopus

  33. MOA-2016-BLG-227Lb: A Massive Planet Characterized by Combining Light-curve Analysis and Keck AO Imaging 査読有り

    Koshimoto N., Shvartzvald Y., Bennett D.P., Penny M.T., Hundertmark M., Bond I.A., Zang W.C., Henderson C.B., Suzuki D., Rattenbury N.J., Sumi T., Abe F., Asakura Y., Bhattacharya A., Donachie M., Evans P., Fukui A., Hirao Y., Itow Y., Li M.C.A., Ling C.H., Masuda K., Matsubara Y., Matsuo T., Muraki Y., Nagakane M., Ohnishi K., Ranc C., Saito T., Sharan A., Shibai H., Sullivan D.J., Tristram P.J., Yamada T., Yamada T., Yonehara A., Gelino C.R., Beichman C., Beaulieu J.P., Marquette J.B., Batista V., Friedmann M., Hallakoun N., Kaspi S., Maoz D., Bryden G., Novati S.C., Howell S.B., Wang T.S., Mao S., Fouqué P., Korhonen H., Jørgensen U.G., Street R., Tsapras Y., Dominik M., Kerins E., Cassan A., Snodgrass C., Bachelet E., Bozza V., Bramich D.M.

    Astronomical Journal   154 巻 ( 1 )   2017年7月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Astronomical Journal  

    We report the discovery of a microlensing planet - MOA-2016-BLG-227Lb - with a large planet/host mass ratio of q ≃ 9 ×10-3. This event was located near the K2 Campaign 9 field that was observed by a large number of telescopes. As a result, the event was in the microlensing survey area of a number of these telescopes, and this enabled good coverage of the planetary light-curve signal. High angular resolution adaptive optics images from the Keck telescope reveal excess flux at the position of the source above the flux of the source star, as indicated by the light-curve model. This excess flux could be due to the lens star, but it could also be due to a companion to the source or lens star, or even an unrelated star. We consider all these possibilities in a Bayesian analysis in the context of a standard Galactic model. Our analysis indicates that it is unlikely that a large fraction of the excess flux comes from the lens, unless solar-type stars are much more likely to host planets of this mass ratio than lower mass stars. We recommend that a method similar to the one developed in this paper be used for other events with high angular resolution follow-up observations when the follow-up observations are insufficient to measure the lens-source relative proper motion.

    DOI: 10.3847/1538-3881/aa72e0

    Web of Science

    Scopus

    arXiv

  34. MOA-2012-BLG-505Lb: A Super-Earth-mass Planet That Probably Resides in the Galactic Bulge 査読有り

    Nagakane M., Sumi T., Koshimoto N., Bennett D., Bond I., Rattenbury N., Suzuki D., Abe F., Asakura Y., Barry R., Bhattacharya A., Donachie M., Fukui A., Hirao Y., Itow Y., Li M., Ling C., Masuda K., Matsubara Y., Matsuo T., Muraki Y., Ohnishi K., Ranc C., Saito T., Sharan A., Shibai H., Sullivan D., Tristram P., Yamada T., Yonehara A.

    Astronomical Journal   154 巻 ( 1 )   2017年7月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Astronomical Journal  

    We report the discovery of a super-Earth-mass planet in the microlensing event MOA-2012-BLG-505. This event has the second shortest event timescale of t E = 10 ± 1 days where the observed data show evidence of a planetary companion. Our 15 minute high cadence survey observation schedule revealed the short subtle planetary signature. The system shows the well known close/wide degeneracy. The planet/host-star mass ratio is q = 2.1 times; 10-4 and the projected separation normalized by the Einstein radius is s = 1.1 or 0.9 for the wide and close solutions, respectively. We estimate the physical parameters of the system by using a Bayesian analysis and find that the lens consists of a super-Earth with a mass of 6.7 10.7-3.6 M⊕ orbiting around a brown dwarf or late-M-dwarf host with a mass of 0.10 +0.16-0.05 M⊙ with a projected star-planet separation of 0.9+0.30.2. The system is at a distance of 7.2 ± 1.1 kpc, i.e., it is likely to be in the Galactic bulge. The small angular Einstein radius (θ E = 0.12 ± 0.02 mas) and short event timescale are typical for a low-mass lens in the Galactic bulge. Such low-mass planetary systems in the Bulge are rare because the detection efficiency of planets in short microlensing events is relatively low. This discovery may suggest that such low-mass planetary systems are abundant in the Bulge and currently on-going high cadence survey programs will detect more such events and may reveal an abundance of such planetary systems.

    DOI: 10.3847/1538-3881/aa74b2

    Web of Science

    Scopus

    arXiv

  35. The SEEDS High-Contrast Imaging Survey of Exoplanets Around Young Stellar Objects 査読有り

    Taichi Uyama, Jun Hashimoto, Masayuki Kuzuhara, Satoshi Mayama, Eiji Akiyama, Thayne Currie, John Livingston, Tomoyuki Kudo, Nobuhiko Kusakabe, Lyu Abe, Wolfgang Brandner, Timothy D. Brandt, Joseph C. Carson, Sebastian Egner, Markus Feldt, Miwa Goto, Carol A. Grady, Olivier Guyon, Yutaka Hayano, Masahiko Hayashi, Saeko S. Hayashi, Thomas Henning, Klaus W. Hodapp, Miki Ishii, Masanori Iye, Markus Janson, Ryo Kandori, Gillian R. Knapp, Jungmi Kwon, Taro Matsuo, Michael W. Mcelwain, Shoken Miyama, Jun-Ichi Morino, Amaya Moro-Martin, Tetsuo Nishimura, Tae-Soo Pyo, Eugene Serabyn, Takuya Suenaga, Hiroshi Suto, Ryuji Suzuki, Yasuhiro H. Takahashi, Michihiro Takami, Naruhisa Takato, Hiroshi Terada, Christian Thalmann, Edwin L. Turner, Makoto Watanabe, John Wisniewski, Toru Yamada, Hideki Takami, Tomonori Usuda, Motohide Tamura

    ASTRONOMICAL JOURNAL   153 巻 ( 3 )   2017年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IOP PUBLISHING LTD  

    We present high-contrast observations of 68 young stellar objects (YSOs) that have been explored as part of the Strategic Exploration of Exoplanets and Disks with Subaru (SEEDS) survey on the Subaru telescope. Our targets are very young (<10Myr) stars, which often harbor protoplanetary disks where planets may be forming. We achieve a typical contrast of similar to 10(-4)-10(-5.5) at an angular distance of 1" from the central star, corresponding to typical mass sensitivities (assuming hot-start evolutionary models) of similar to 10 M-J at 70 au and similar to 6 M-J at 140 au. We detected a new stellar companion to HIP 79462 and confirmed the substellar objects GQ Lup b and ROXs 42B b. An additional six companion candidates await follow-up observations to check for common proper motion. Our SEEDS YSO observations probe the population of planets and brown dwarfs at the very youngest ages; these may be compared to the results of surveys targeting somewhat older stars. Our sample and the associated observational results will help enable detailed statistical analyses of giant planet formation.

    DOI: 10.3847/1538-3881/153/3/106

    Web of Science

    arXiv

  36. Radial decoupling of small and large dust grains in the transitional disk RX J1615.3-3255 査読有り

    Kooistra R., Kamp I., Fukagawa M., Ménard F., Momose M., Tsukagoshi T., Kudo T., Kusakabe N., Hashimoto J., Abe L., Brandner W., Brandt T.D., Carson J.C., Egner S.E., Feldt M., Goto M., Grady C.A., Guyon O., Hayano Y., Hayashi M., Hayashi S.S., Henning T., Hodapp K.W., Ishii M., Iye M., Janson M., Kandori R., Knapp G.R., Kuzuhara M., Kwon J., Matsuo T., McElwain M.W., Miyama S., Morino J.I., Moro-Martin A., Nishimura T., Pyo T.S., Serabyn E., Suenaga T., Suto H., Suzuki R., Takahashi Y.H., Takami M., Takato N., Terada H., Thalmann C., Tomono D., Turner E.L., Watanabe M., Wisniewski J., Yamada T., Takami H., Usuda T., Tamura M., Currie T., Akiyama E., Mayama S., Follette K.B., Nakagawa T.

    Astronomy and Astrophysics   597 巻   2017年1月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Astronomy and Astrophysics  

    We present H-band (1.6 μm) scattered light observations of the transitional disk RX J1615.3-3255, located in the ∼1 Myr old Lupus association. From a polarized intensity image, taken with the HiCIAO instrument of the Subaru Telescope, we deduce the position angle and the inclination angle of the disk. The disk is found to extend out to 68 ± 12 AU in scattered light and no clear structure is observed. Our inner working angle of 24 AU does not allow us to detect a central decrease in intensity similar to that seen at 30 AU in the 880 μm continuum observations. We compare the observations with multiple disk models based on the spectral energy distribution (SED) and submm interferometry and find that an inner rim of the outer disk at 30 AU containing small silicate grains produces a polarized intensity signal which is an order of magnitude larger than observed. We show that a model in which the small dust grains extend smoothly into the cavity found for large grains is closer to the actual H-band observations. A comparison of models with different dust size distributions suggests that the dust in the disk might have undergone significant processing compared to the interstellar medium.

    DOI: 10.1051/0004-6361/201628696

    Web of Science

    Scopus

    arXiv

  37. OGLE-2012-BLG-0950Lb: The FIRST PLANET MASS MEASUREMENT from only MICROLENS PARALLAX and LENS FLUX 査読有り

    Koshimoto N., Udalski A., Beaulieu J.P., Sumi T., Bennett D.P., Bond I.A., Rattenbury N., Fukui A., Batista V., Marquette J.B., Brillant S., Abe F., Asakura Y., Bhattacharya A., Donachie M., Freeman M., Hirao Y., Itow Y., Li M.C.A., Ling C.H., Masuda K., Matsubara Y., Matsuo T., Muraki Y., Nagakane M., Ohnishi K., Oyokawa H., Saito T., Sharan A., Shibai H., Sullivan D.J., Suzuki D., Tristram P.J., Yonehara A., Kozłowski S., Pietrukowicz P., Poleski R., Skowron J., Soszyński I., Szymański M.K., Ulaczyk K., Wyrzykowski

    Astronomical Journal   153 巻 ( 1 )   2017年1月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Astronomical Journal  

    We report the discovery of a microlensing planet OGLE-2012-BLG-0950Lb with a planet/host mass ratio of q ≃ 2 10-4. A long term distortion detected in both MOA and OGLE light curve can be explained by the microlens parallax due to the Earths orbital motion around the Sun. Although the finite source effect is not detected, we obtain the lens flux by the high resolution Keck AO observation. Combining the microlens parallax and the lens flux reveal the nature of the lens: a planet with mass of = Mp=35+17-9is orbiting around an M-dwarf with mass of =Mhost=0.56+0.12-0.16Ṁwith a planet-host projected separation of = r⊥=2.7+0.6-0.7 au located at = - DL 3.0+ 0.8-1.1kpc from us. This is the first mass measurement from only microlens parallax and the lens flux without the finite source effect. In the coming space observation-era with Spitzer, K2, Euclid, and WFIRST, we expect many such events for which we will not be able to measure any finite source effect. This work demonstrates an ability of mass measurements in such events.

    DOI: 10.3847/1538-3881/153/1/1

    Web of Science

    Scopus

  38. NEAR-INFRARED IMAGING POLARIMETRY OF INNER REGION OF GG TAU A DISK 査読有り

    Yi Yang, Jun Hashimoto, Saeko S. Hayashi, Motohide Tamura, Satoshi Mayama, Roman Rafikov, Eiji Akiyama, Joseph C. Carson, Markus Janson, Jungmi Kwon, Jerome De Leon, Daehyeon Oh, Michihiro Takami, Ya-Wen Tang, Tomoyuki Kudo, Nobuhiko Kusakabe, Lyu Abe, Wolfgang Brandner, Timothy D. Brandt, Sebastian Egner, Markus Feldt, Miwa Goto, Carol A. Grady, Olivier Guyon, Yutaka Hayano, Masahiko Hayashi, Thomas Henning, Klaus W. Hodapp, Miki Ishii, Masanori Iye, Ryo Kandori, Gillian R. Knapp, Masayuki Kuzuhara, Taro Matsuo, Michael W. Mcelwain, Shoken Miyama, Jun-Ichi Morino, Amaya Moro-Martin, Tetsuo Nishimura, Tae-Soo Pyo, Eugene Serabyn, Takuya Suenaga, Hiroshi Suto, Ryuji Suzuki, Yasuhiro H. Takahashi, Naruhisa Takato, Hiroshi Terada, Christian Thalmann, Edwin L. Turner, Makoto Watanabe, John Wisniewski, Toru Yamada, Hideki Takami, Tomonori Usuda

    ASTRONOMICAL JOURNAL   153 巻 ( 1 )   2017年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IOP PUBLISHING LTD  

    By performing non-masked polarization imaging with Subaru/HiCIAO, polarized scattered light from the inner region of the disk around the GG Tau A system was successfully detected in the H band, with a spatial resolution of approximately 0 07, revealing the complicated inner disk structures around this young binary. This paper reports the observation of an arc-like structure to the north of GG Tau Ab, and part of a circumstellar structure that is noticeable around GG Tau Aa, extending to a distance of approximately 28 au from the primary star. The speckle noise around GG Tau Ab constrains its disk radius to < 13 au. Based on the size of the circumbinary ring and the circumstellar disk around GG Tau Aa, the semimajor axis of the binary's orbit is likely to be 62 au. A comparison of the present observations with previous Atacama Large Millimeter Array and near-infrared H-2 emission observations suggests that the north arc could be part of a large streamer flowing from the circumbinary ring to sustain the circumstellar disks. According to the previous studies, the circumstellar disk around GG Tau Aa has enough mass and can sustain itself for a duration sufficient for planet formation; thus, our study indicates that planets can form within close (separation. 100 au) young binary systems.

    DOI: 10.3847/1538-3881/153/1/7

    Web of Science

    arXiv

▼全件表示

MISC 2

  1. SUBARU Near-Infrared Imaging Polarimetry of Misaligned Disks Around The SR24 Hierarchical Triple System

    Satoshi Mayama, Sebastián Pérez, Nobuhiko Kusakabe, Takayuki Muto, Takashi Tsukagoshi, Michael L. Sitko, Michihiro Takami, Jun Hashimoto, Ruobing Dong, Jungmi Kwon, Saeko S. Hayashi, Tomoyuki Kudo, Masayuki Kuzuhara, Kate B. Follette, Misato Fukagawa, Munetake Momose, Daehyeon Oh, Jerome De Leon, Eiji Akiyama, John P. Wisniewski, Yi Yang, Lyu Abe, Wolfgang Brandner, Timothy D. Brandt, Michael Bonnefoy, Joseph C. Carson, Jeffrey Chilcote, Thayne Currie, Markus Feldt, Miwa Goto, Tyler Groff, Olivier Guyon, Yutaka Hayano, Masahiko Hayashi, Thomas Henning, Klaus W. Hodapp, Miki Ishii, Masanori Iye, Markus Janson, Nemanja Jovanovic, Ryo Kandori, Jeremy Kasdin, Gillian R. Knapp, Julien Lozi, Frantz Martinache, Taro Matsuo, Michael W. Mcelwain, Shoken Miyama, Jun-ichi Morino, Amaya Moro-martin, Takao Nakagawa, Tetsuo Nishimura, Tae-soo Pyo, Evan A. Rich, Eugene Serabyn, Hiroshi Suto, Ryuji Suzuki, Naruhisa Takato, Hiroshi Terada, Christian Thalmann, Daigo Tomono, Edwin L. Turner, Makoto Watanabe, Toru Yamada, Hideki Takami, Tomonori Usuda, Taichi Uyama, Motohide Tamura  

        2019年11月

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    記述言語:英語  

    The SR24 multi-star system hosts both circumprimary and circumsecondary
    disks, which are strongly misaligned from each other. The circumsecondary disk
    is circumbinary in nature. Interestingly, both disks are interacting, and they
    possibly rotate in opposite directions. To investigate the nature of this
    unique twin disk system, we present 0.''1 resolution near-infrared polarized
    intensity images of the circumstellar structures around SR24, obtained with
    HiCIAO mounted on the Subaru 8.2 m telescope. Both the circumprimary disk and
    the circumsecondary disk are resolved and have elongated features. While the
    position angle of the major axis and radius of the NIR polarization disk around
    SR24S are 55$^{\circ}$ and 137 au, respectively, those around SR24N are
    110$^{\circ}$ and 34 au, respectively. With regard to overall morphology, the
    circumprimary disk around SR24S shows strong asymmetry, whereas the
    circumsecondary disk around SR24N shows relatively strong symmetry. Our NIR
    observations confirm the previous claim that the circumprimary and
    circumsecondary disks are misaligned from each other. Both the circumprimary
    and circumsecondary disks show similar structures in $^{12}$CO observations in
    terms of its size and elongation direction. This consistency is because both
    NIR and $^{12}$CO are tracing surface layers of the flared disks. As the radius
    of the polarization disk around SR24N is roughly consistent with the size of
    the outer Roche lobe, it is natural to interpret the polarization disk around
    SR24N as a circumbinary disk surrounding the SR24Nb-Nc system.

    DOI: 10.3847/1538-3881/ab5850

    arXiv

  2. Point Spread Function of Hexagonally Segmented Telescopes by New Symmetrical Formulation

    Satoshi Itoh, Taro Matsuo, Shibai Hiroshi, Takahiro Sumi  

        2018年11月

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    A point spread function of hexagonally segmented telescopes is derived by a
    new symmetrical formulation. By introducing three variables on a pupil plane,
    the Fourier transform of pupil functions is derived by a three-dimensional
    Fourier transform. The permutations of three variables correspond to those of a
    regular triangle's vertices on the pupil plane. The resultant diffraction
    amplitude can be written as a product of two functions of the three variables;
    the functions correspond to the sinc function and Dirichlet kernel used in the
    basic theory of diffraction gratings. The new expression makes it clear that
    hexagonally segmented telescopes are equivalent to diffraction gratings in
    terms of mathematical formulae.

    DOI: 10.1093/mnras/sty3052

    arXiv

科研費 6

  1. 地球型系外惑星大気の特徴づけのための精密分光方式の確立

    研究課題/研究課題番号:19H00700  2019年4月 - 2022年3月

    日本学術振興会  科学研究費助成事業  基盤研究(A)

    松尾 太郎, 芝井 広

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    担当区分:研究代表者 

    配分額:42900000円 ( 直接経費:33000000円 、 間接経費:9900000円 )

    太陽系外の恒星の周りで3000を超える系外惑星が発見されている。系外惑星の中には、地球と同程度の大きさで、かつ主星からほどよい距離にある水を保有する可能性のある生命居住可能惑星が含まれる。本研究は、地球型系外惑星の大気分光のために、太陽系近傍の食を起こす地球型系外惑星の分光観測ための技術を確立するものである。2016年に提案された瞳収縮分光は、望遠鏡の姿勢変化や検出器ゲインの時間変化の影響を抑えて、10万分の1の測光分光の安定性を達成できる可能性が示された。本研究は、宇宙観測環境を模擬する望遠鏡シミュレータを開発し、観測環境下での瞳収縮分光器の性能を評価する。
    2019年度は、瞳収縮分光器の実験において次の大きな進展があった。一つ目の進展は、Matsuo et al. (2016)の論文で述べた理論の通りに正しく瞳収縮分光器の分光像が取得されたことである。瞳収縮分光器は、瞳を分割・収縮することによって、光の回折を起こして、分光器内で波動光学的な伝搬を利用するものである。ちなみに、従来の分光方式では、分光器内は幾何光学的な伝搬である。つまり、瞳収縮分光器は、従来の分光器と比べて全く新しい方法を利用した分光器である。この瞳収縮分光器の像が予想通りに取得できたことは、分光器の内部を光が波動光学的に伝搬していることを示しており、実験実証に成功したと考えている。
    二つ目の進展は、中間赤外線検出器システム単体での安定性の評価を実施したことである。これまで、検出器単体の安定性を評価することができなかった。NASA Ames Reserach Centerとの協力において、検出器の安定性評価のための実験環境を整備し、12時間以上にわたって検出器の安定性を評価した。その結果、検出器システムの安定性を数ppmレベルで評価することに成功し、検出器単体では30 ppmの安定性に制限されることが分かった。さらに、瞳収縮分光器で取得される像のように多数のピクセルで光を検出する場合には、その安定性が数ppmレベルまで改善されることが分かった。この結果は、Matsuo et al. PASP, Vol. 131, pp. 124502に出版された。
    最後の進展は、この実験環境を瞳収縮分光器の実験にも応用し、瞳収縮分光器の安定性の評価を行なった。その結果、系統誤差は10ppmレベルにまで抑えることができ、本プロジェクトの目標の一つをクリアできた。この結果は、2020年のSPIEの国際会議で報告された。
    2019年度の当初の目標は、瞳収縮分光器の実証実験と望遠鏡の姿勢を模擬する望遠鏡シミュレーターの製作を行うことであった。前者については、研究実績の概要において述べたように、分光器の安定性を評価するための実験環境を作成することに成功し、瞳収縮分光器の実証実験の中で安定性の評価が実施できた。一方の後者については、望遠鏡シミュレーターの設計および物品の選定は固まったものの製作までには至らなかった。ただし、2020年末に望遠鏡シミュレーターが完成し、実証実験に必要な仕様を満たしていることが確認できた。以上より、当初計画していた項目の全てを完了することはできなかったものの、本プロジェクトにおいてクリティカルな項目の多くをクリアしたと考えている。
    望遠鏡の姿勢を模擬する望遠鏡シミュレーターが完成した。今後、望遠鏡シミュレーターをNASA Ames Research Centerに輸送し、そのシミュレーターに中間赤外線検出器を取り付けて、極低温下においてシミュレーターが動作することを確認する。さらに、シミュレーターと瞳収縮分光器の接続に問題ないかを確認した後に、シミュレーターで望遠鏡の姿勢を模擬した光を瞳収縮分光器に導入する。姿勢の変化に対する分光像の安定性を評価し、瞳収縮分光器によって検出器に形成される瞳分光像の有用性を評価する。

  2. 遠赤外線点源の気球搭載干渉計による高解像観測

    研究課題/研究課題番号:18H01255  2018年4月 - 2021年3月

    日本学術振興会  科学研究費助成事業  基盤研究(B)

    芝井 広, 松尾 太郎

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    担当区分:研究分担者 

    科学観測用大気球に搭載する宇宙遠赤外線干渉計(FITE)を、オーストラリア・アリススプリングス気球基地から打上げ、晩期型赤色超巨星の高解像秒角撮像を行う計画を進めた。気象条件が適わずに打上は実施できなかったが、次の機会のために装置の整備・維持を継続した。これによって、複雑かつ精密な光学装置を、打上基地現地で短期間で調整する方法を確立し、遠赤外線において高解像撮像をするシステムの開発を完了した。
    宇宙の諸現象はあらゆる電磁波を発生する。遠赤外線には原子・分子や有機物質のスペクトルが多く属しており、物質、惑星、生命誕生課程の研究には欠かせない波長帯である。しかしこの波長帯の解像度の点については、地球大気による吸収と回折限界の壁によって進んでいない。この限界を乗り越えるために世界初の遠赤外線干渉計望遠鏡技術を実証したことに意義がある。将来の本格的スペース干渉計望遠鏡実現への重要な一歩である。

  3. 科学衛星の観測環境を模擬した地球型系外惑星観測のための高安定分光器の性能評価

    研究課題/研究課題番号:17KK0090  2018年 - 2019年

    日本学術振興会  科学研究費助成事業  国際共同研究加速基金(国際共同研究強化)

    松尾 太郎

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    担当区分:研究代表者 

    配分額:14300000円 ( 直接経費:11000000円 、 間接経費:3300000円 )

    本研究は、NASA Ames Research Centerと協力して、太陽系近傍にある地球サイズの惑星の大気分光を行い、その惑星の表層環境や生命活動の有無を調査することを目的とした技術を確立するものである。本技術は、瞳収縮分光と呼ばれる、従来の焦点面分光と180度異なる概念の分光器である。この分光器は、原理的に望遠鏡の姿勢や主鏡の歪みの影響を全く受けないため、安定して惑星大気を分光することができる。本研究期間において、中間赤外線の波長帯域において瞳収縮分光の像を取得することに成功し、さらに100万分の10という分光測光精度を達成した。地球型系外惑星の大気を分光する新しい手法を確立した。
    2009年に打ち上げられたKepler衛星によって、地球サイズの太陽系外惑星は宇宙に普遍的に存在することが明らかにされた。さらに、2018年に打ち上げが成功した、Transiting Exoplanets Survey Satellite (TESS)や地上望遠鏡によって、太陽系近傍において続々と食を起こす地球サイズの惑星が発見されている。この食を起こす惑星の表層環境や生命活動の有無を調査することが今後20年の目標である。本研究は、食を起こす惑星の大気を精密に分光する新しい瞳収縮分光技術をNASAと協力しながら確立し、将来の大型宇宙望遠鏡において実現する道筋を作ることができた。

  4. 近赤外線重力マイクロレンズ観測による冷たい系外惑星及び 浮遊惑星の探索

    研究課題/研究課題番号:16H06287  2016年4月 - 2021年3月

    日本学術振興会  科学研究費助成事業  特別推進研究

    住 貴宏, 松尾 太郎, 村木 綏, 松永 典之, 芝井 広, 阿部 文雄

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    担当区分:研究分担者 

    本研究は、南アフリカ共和国に1.8m広視野望遠鏡を建設し、世界最大級の近赤外線カメラを搭載して、世界で初めて近赤外線での重力マイクロレンズ系外惑星探 査を行う(PRime-focus Infrared Microlensing Experiment:PRIME)。背景天体の前を他の星(レンズ天体)が通過すると、その重力がレンズの様な働きをして背景天体からの光を一時的に増光し、マイクロレンズイベントとして観測される。この時レンズ天体の周りに惑星があると、その重力によりさらにレンズを受け検出 される。これまで、我々MOAグループは可視光で観測してきたが、近赤外線では可視光に比べて以下の利点がある。星間減光が強い銀河系中心近くを観測可能。星数密度が高く惑星発見数が増加。星数密度が高い領域での惑星頻度を世界で初めて見積もり、環境による違いを検証可能。これらにより惑星形成、進化の過程を解明する。本研究は、2025年頃打ち上げ予定のNASAのWFIRST衛星への日本の貢献でもある。本年度は、MOA-II望遠鏡による高銀緯バルジの観測は計画通り続けた。この期間に、系外惑星候補を4 個発見し、大学院生や海外の共同研究者達と共にデータ解析をして成果としてまとめている。これら高銀緯領域の結果は、本研究の成果と比較するために必須であるが、順調に成果を出せている。望遠鏡製作に関しては、1年遅れていること以外は順調に進んでおり、本年度は、1.8m主焦点広視野望遠鏡用の主鏡の製作が完了し、さらに望遠鏡全体の組み立てを完了した。南アフリカ天文台は、望遠鏡を格納する建物の詳細設計を完了して、現在、建設のための入札を行なっている。 カメラ製作に関しては、1年程度遅れが生じているが、それ以外は大きな変更はない。本年度は、カメラのプロトタイプの製作を完了し、冷却試験等を実施して、観測用の実機製作の準備を整えた。
    MOA-II望遠鏡による高銀緯バルジの観測は計画通り続けた。経験を積ませるために、大学院生等のべ31人が現地で観測をした。この期間に、系外惑星候補を約14個発見し、大学院生や海外の共同研究者達と共にデータ解析をして成果としてまとめている。これら高銀緯領域の結果は、本研究の成果と比較するために必須であるが、順調に成果を出せている。望遠鏡に関しては、諸事情のために1年程度遅れが生じているが、それ以外は大きな変更もなく順調に進んでいる。本年度は、1.8m主焦点広視野望遠鏡用の主鏡の製作が完了し、さらに望遠鏡全体の組み立てを完了した。南アフリカ天文台は、望遠鏡を格納する建物の詳細設計を完了して、現在、建設のための入札を行なっている。 カメラ製作に関しては、1年程度遅れが生じているが、それ以外は大きな変更はない。
    大阪大学は、メリーランド大学と協力して、NASA WFIRST衛星計画から近赤外検出器を借り受け、広視野赤外線カメラをNASAのゴダードセンター(GSFC)で製作する計画である。カメラ製作に関しても大きな変更はないが、1年程度遅れが生じている。これは、カメラ製作に関してNASA本部、NASA/GSFC、WFIRSTプロジェクト、メリーランド大の関係各所で、ゴ ダードでの実際の実験室使用許可や赤外線検出器のITAR(武器国際取引に関する規則)をクリアする道筋を見極めるのに時間を要したからである。また、WFIRST全体に関するNASA-JAXA間の合意も必要であったが、米国大統領予算でWFIRST計画に一時的な不透明性が生じたため、合意に時間を要したことも影響している。現在はNASA-JAXA間で合意文章にサインされて、製作を進める準備が整った。本年度は、カメラのプロトタイプの製作を完了し、冷却試験等を実施して、観測用の実機製作の準備を整えた。
    MOA-II望遠鏡による高銀緯バルジの観測はこれまで通り続ける。バルジが観測可能な3月から11月に22領域( 50平方度)を観測する 。7月頃は、この領域を1日10- 50回も観測できる。従来は、日本のメンバーが現地に行き観測してきたが、 現在はニュージーランド現地観測員を増やし、本研究の主要メンバーとは独立に、ニュージーランドメンバーと運営できる体制に移行しており、我々は新広視野近赤外望遠鏡建設に集中できる。ただ、新望遠鏡完成までは、観測経験を積むために本研究の大学院生も観測に派遣する。MOAメンバーのD.Bennett 氏(NASA/GSFS、米国)やIan Bond氏(マッシー大学、NZ)が中心となり大学院生と共にデータ解析をして成果を論文にまとめて、PRIMEの赤外線観測の成果と比較できる様にする。また、望遠鏡製作に関しては、南アフリカ天文台と協力して、観測所にドーム建物、コントロールルームを建設をする予定である。そして、新広視野近赤外望遠鏡を、南アフリカ、サザーランド観測所にインストールする予定である。ここで、望遠鏡を制御するシステム(PC及びソフトフェア)を現地で構築し、定常観測ができる様にする。Alexaner Kutyrev氏(NASA/GSFS、メリーラン ド大、米国)らは、NASAのゴダードでWFIRSTチームが所有している H4RG近赤外線検出器4枚を使い、カメラ本体、冷却系及びフィルター交換装置の実機の製作を始める。 ここで、米国現地に滞在する大学院生もこれまで通り、NASA、メリーランド大のグループとの連携を計り開発に参加する。さらに、南アフリカ、サザーランド天文台現地に設置する計算機を用意して、Difference Image analysis (DIA)を用いたリアルタイムデータ解析パイプラインの移植も進める。

  5. 地球型系外惑星の熱放射観測のための超高安定分光装置の開発と宇宙望遠鏡への提案

    研究課題/研究課題番号:16H02164  2016年4月 - 2019年3月

    日本学術振興会  科学研究費助成事業  基盤研究(A)

    松尾 太郎, 芝井 広, 住 貴宏

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    担当区分:研究代表者 

    配分額:37180000円 ( 直接経費:28600000円 、 間接経費:8580000円 )

    太陽系外の恒星を周回する地球型系外惑星の食分光による大気分光のために、10万分の1の精度が要求される。私たちは、10万分の1を超える高精度の分光測光装置(瞳収縮分光器)を提案し、試験機として製作に成功した。また、本装置コンセプトは、NASAが計画する将来の極低温大型宇宙望遠鏡(Origins Space Telescope: OST)のベースライン装置として採用され、これらの成果がUS 2020 Decadal Surveyへ提出されるOSTの提案書へ載せられることになった。今後、NASAとの協力の下、極低温環境において試験機の安定性を10万分の1の精度で評価する予定である。
    本研究は、中間赤外線での地球型系外惑星の分光観測に新しい道を切り拓くものである。中間赤外線には、オゾンやメタンといった地球生命が光合成や代謝によって生成される分子の吸収線が存在する。したがって、系外惑星の大気の非平衡性を分光観測において調査することで、生命の存在有無を推定することが可能になる。本研究において、中間赤外線での生命探査を実現する新しい装置概念を創案し、その試験機の開発に成功した。本研究において開発された技術が基盤となり、人類が長年抱いてきた「宇宙における生命の可能性」という究極的な課題に挑むことが期待される。

  6. 次世代大型望遠鏡における地球型系外惑星の撮像分光装置の研究

    研究課題/研究課題番号:25247021  2013年4月 - 2017年3月

    日本学術振興会  科学研究費助成事業 基盤研究(A)  基盤研究(A)

    松尾 太郎, 小谷 隆行, 入部 正継, 村上 尚史, Guyon Olivier, 小谷 隆行

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    担当区分:研究代表者 

    配分額:41080000円 ( 直接経費:31600000円 、 間接経費:9480000円 )

    Thirty Meter Telescope (TMT)をはじめとした次世代の地上大型望遠鏡において地球型系外惑星の観測において、地球大気の乱流によって乱れる波面をリアルタイムに高精度で補償することは最も重要である。本開発では、その補償光学の要素開発を室内で行い、また、次世代の補償光学系のための新しい計測技術を考案した。これらの要素開発は、本科研費で閉じることなく、京大岡山3.8m望遠鏡において本科研費で開発された補償光学による系外惑星の観測がその発展として行われる予定である。

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担当経験のある科目 (本学) 1

  1. 3年物理学実験

    2020

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    3年生の回路の基本的な特性を理解し、その基本的な理解に基づいて回路を用いて信号取得などを実施する物理学実験である。

担当経験のある科目 (本学以外) 5

  1. 先端物理学特論

    2021年4月 名古屋大学)

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    科目区分:学部専門科目 

  2. 3年物理学実験

    2020年4月 - 現在 名古屋大学)

  3. 物理学実験基礎

    2018年10月 - 2019年10月 大阪大学)

  4. 宇宙生命論(リレー講義)

    2015年10月 - 2019年10月 大阪大学)

  5. 3年物理学実験

    2015年10月 - 2018年9月 大阪大学)

 

社会貢献活動 7

  1. 科学三昧inあいち

    役割:助言・指導, 実演

    2020年12月

  2. 出前授業:太陽系外惑星科学の最前線「宇宙における生命探査」

    役割:講師

    府立園部附属中学校  2018年11月

  3. 出前授業:太陽系外惑星科学の現在と将来

    役割:講師

    府立東宇治高等学校  2017年12月

  4. 出前授業:太陽系外惑星科学の最前線「宇宙における生命探査」

    役割:講師

    亀岡市立詳徳中学校  2017年12月

  5. 出前授業:宇宙生命を探せ!

    役割:講師

    京田辺市立薪小学校  2017年10月

  6. 太陽系外惑星科学の現在と未来 〜 私がこれから30年かけて取り組みたいこと〜

    役割:講師

    高校生天文活動発表会実行委員会  2017年7月

  7. 太陽系惑星と太陽系外惑星に関するセミナー

    役割:講師

    NPO花山星空ネットワーク  2012年4月 - 2017年3月

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