HISAKI Project Team
  1. 研究者リスト
  2. 臼井 文彦

臼井 文彦

ウスイ フミヒコ  (Fumihiko Usui)

基本情報

所属
国立研究開発法人宇宙航空研究開発機構 宇宙科学研究所 主任研究開発員
学位
修士（学術）(東京大学)
博士（理学）(東京大学)
ORCID ID
 https://orcid.org/0000-0003-2273-0103
J-GLOBAL ID
201601015297652541
researchmap会員ID
7000017299

研究分野

 2

経歴

 7
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学歴

 4

受賞

 2

論文

 148
  • Daisuke Kawata, Hajime Kawahara, Naoteru Gouda, Nathan J Secrest, Ryouhei Kano, Hirokazu Kataza, Naoki Isobe, Ryou Ohsawa, Fumihiko Usui, Yoshiyuki Yamada, Alister W Graham, Alex R Pettitt, Hideki Asada, Junichi Baba, Kenji Bekki, Bryan N Dorland, Michiko Fujii, Akihiko Fukui, Kohei Hattori, Teruyuki Hirano, Takafumi Kamizuka, Shingo Kashima, Norita Kawanaka, Yui Kawashima, Sergei A Klioner, Takanori Kodama, Naoki Koshimoto, Takayuki Kotani, Masayuki Kuzuhara, Stephen E Levine, Steven R Majewski, Kento Masuda, Noriyuki Matsunaga, Kohei Miyakawa, Makoko Miyoshi, Kumiko Morihana, Ryoichi Nishi, Yuta Notsu, Masashi Omiya, Jason Sanders, Ataru Tanikawa, Masahiro Tsujimoto, Taihei Yano, Masataka Aizawa, Ko Arimatsu, Michael Biermann, Celine Boehm, Masashi Chiba, Victor P Debattista, Ortwin Gerhard, Masayuki Hirabayashi, David Hobbs, Bungo Ikenoue, Hideyuki Izumiura, Carme Jordi, Naoki Kohara, Wolfgang Löffler, Xavier Luri, Ichiro Mase, Andrea Miglio, Kazuhisa Mitsuda, Trent Newswander, Shogo Nishiyama, Yoshiyuki Obuchi, Takafumi Ootsubo, Masami Ouchi, Masanobu Ozaki, Michael Perryman, Timo Prusti, Pau Ramos, Justin I Read, R Michael Rich, Ralph Schönrich, Minori Shikauchi, Risa Shimizu, Yoshinori Suematsu, Shotaro Tada, Aoi Takahashi, Takayuki Tatekawa, Daisuke Tatsumi, Takuji Tsujimoto, Toshihiro Tsuzuki, Seitaro Urakawa, Fumihiro Uraguchi, Shin Utsunomiya, Vincent Van Eylen, Floor van Leeuwen, Takehiko Wada, Nicholas A Walton
    Publications of the Astronomical Society of Japan 2024年4月10日  
    Abstract The Japan Astrometry Satellite Mission for INfrared Exploration (JASMINE) is a planned M-class science space mission by the Institute of Space and Astronautical Science, the Japan Aerospace Exploration Agency. JASMINE has two main science goals. One is Galactic archaeology with a Galactic Center survey, which aims to reveal the Milky Way’s central core structure and formation history from Gaia-level (∼25 ${\mu} $as) astrometry in the near-infrared (NIR) Hw band (1.0–1.6 ${\mu} $m). The other is an exoplanet survey, which aims to discover transiting Earth-like exoplanets in the habitable zone from NIR time-series photometry of M dwarfs when the Galactic Center is not accessible. We introduce the mission, review many science objectives, and present the instrument concept. JASMINE will be the first dedicated NIR astrometry space mission and provide precise astrometric information on the stars in the Galactic Center, taking advantage of the significantly lower extinction in the NIR. The precise astrometry is obtained by taking many short-exposure images. Hence, the JASMINE Galactic Center survey data will be valuable for studies of exoplanet transits, asteroseismology, variable stars, and microlensing studies, including discovery of (intermediate-mass) black holes. We highlight a swath of such potential science, and also describe synergies with other missions.
  • K. Arimatsu, K. Tsumura, F. Usui, J. Watanabe
    Astronomy & Astrophysics 2023年8月23日  
  • Ko Arimatsu, Kohji Tsumura, Fumihiko Usui, Jun-ichi Watanabe
    Monthly Notices of the Royal Astronomical Society 2023年4月7日  
    Abstract We have conducted numerical simulations to reproduce the observed optical energy profile of the 15 October 2021 (UT) impact flash on Jupiter, which was the largest and the most well-observed flash event detected by ground-based movie observations. The observed long-duration (∼5.5 s) optical emission can be reproduced by an impact of an object with an exceptionally small angle of entry relative to the horizontal. The apparent lack of the impact debris feature despite the large impact object was possibly due to the shallower angle of entry (≤12○), which resulted in the lower ablation per unit volume at altitudes higher than 50 km, and the volume densities of the ablated materials were too low to allow the debris particulates to coagulate. The absence of temporal methane absorption change in the observed flash spectrum is consistent with the best-fit results. The model better fits the observed optical energy profile for weaker material (cometary and stony) cases than for metallic ones. Based on the simulation results, prospects for future observations of impact flashes are discussed.
  • Takafumi Kamizuka, Takashi Miyata, Shigeyuki Sako, Ryou Ohsawa, Kentaro Asano, Atsushi Nishimura, Kengo Tachibana, Tsubasa Michifuji, Hirokazu Iida, Akira C. Naruse, Mizuho Uchiyama, Itsuki Sakon, Takashi Onaka, Hirokazu Kataza, Sunao Hasegawa, Fumihiko Usui, Naruhisa Takato, Noboru Ebizuka, Takuya Hosobata, Tsutomu Aoki, Mamoru Doi, Fumi Egusa, Bunyo Hatsukade, Natsuko Kato, Kotaro Kohno, Masahiro Konishi, Shintaro Koshida, Shuhei Koyama, Takeo Minezaki, Tomoki Morokuma, Kentaro Motohara, Mizuki Numata, Hiroaki Sameshima, Hidenori Takahashi, Yoichi Tamura, Toshihiko Tanabe, Masuo Tanaka, Kosuke Kushibiki, Nuo Chen, Shogo Homan, Yuzuru Yoshii
    Proceedings of SPIE, Ground-based and Airborne Instrumentation for Astronomy IX 12184 2022年8月29日  
    MIMIZUKU is the first-generation mid-infrared instrument for the TAO 6.5-m telescope. It has three internal optical channels to cover a wide wavelength range from 2 to 38 mu m. Of the three channels, the NIR channel is responsible for observations in the shortest wavelength range, shorter than 5.3 mu m. The performance of the NIR channel is evaluated in the laboratory. Through the tests, we confirm the followings: 1) the detector (HAWAII-1RG with 5.3-mu m cutoff) likely achieves similar to 80% quantum efficiency; 2) imaging performance is sufficient to achieve seeing-limit spatial resolution; 3) system efficiencies in imaging modes are 2.4-31%; and 4) the system efficiencies in spectroscopic modes is 5-18%. These results suggest that the optical performance of the NIR channel is achieved as expected from characteristics of the optical components. However, calculations of the background levels and on-sky sensitivity based on these results suggest that neutral density (ND) filters are needed to avoid saturation in L'- and M'-band observations and that the ND filters and the entrance window, made of chemical-vapor-deposition (CVD) diamond, significantly degrade the sensitivity in these bands. This means that the use of different window materials and improvements of the detector readout speed are required to achieve both near-infrared and long-wavelength mid-infrared (>30 mu m) observations.
  • Jin Beniyama, Shigeyuki Sako, Ryou Ohsawa, Satoshi Takita, Naoto Kobayashi, Shin-ichiro Okumura, Seitaro Urakawa, Makoto Yoshikawa, Fumihiko Usui, Fumi Yoshida, Mamoru Doi, Yuu Niino, Toshikazu Shigeyama, Masaomi Tanaka, Nozomu Tominaga, Tsutomu Aoki, Noriaki Arima, Ko Arimatsu, Toshihiro Kasuga, Sohei Kondo, Yuki Mori, Hidenori Takahashi, Jun-ichi Watanabe
    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 74(4) 877-903 2022年8月  
    We report the results of video observations of tiny (diameter less than 100 m) near-Earth objects (NEOs) with Tomo-e Gozen on the Kiso 105 cm Schmidt telescope. The rotational period of a tiny asteroid reflects its dynamical history and physical properties since smaller objects are sensitive to the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect. We carried out video observations of 60 tiny NEOs at 2 fps from 2018 to 2021 and successfully derived the rotational periods and axial ratios of 32 NEOs including 13 fast rotators with rotational periods less than 60 s. The fastest rotator found during our survey is 2020 HS7 with a rotational period of 2.99 s. We statistically confirmed that there is a certain number of tiny fast rotators in the NEO population, which have been missed with all previous surveys. We have discovered that the distribution of the tiny NEOs in a diameter and rotational period (D-P) diagram is truncated around a period of 10 s. The truncation with a flat-top shape is not explained well by either a realistic tensile strength of NEOs or the suppression of YORP by meteoroid impacts. We propose that the dependence of the tangential YORP effect on the rotational period potentially explains the observed pattern in the D-P diagram.
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MISC

 133
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講演・口頭発表等

 28
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担当経験のある科目(授業)

 1

所属学協会

 5

共同研究・競争的資金等の研究課題

 7
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