Basic Information

Faculty

• Faculty of Science

Email Address

• Email Address

  kasagi.yui.5ckyoto-u.ac.jp

Professional Memberships

• From 2019, To Present

  日本天文学会

Academic Degree

• 22 Mar. 2024

  総合研究大学院大学博士（理学）

Academic Resume (Undergraduate School/Majors)

• 神戸大学, 理学部物理学科, 卒業

Research History

• From Mar. 2026, To Present

  Kyoto University, Graduate School of Science Division of Physics and Astronomy, 助教
• From Apr. 2024, To Feb. 2026

  Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, Department of Space Astronomy and Astrophysics, Aerospace Project Research Associate

ID,URL

• ORCID ID

  0000-0002-8607-358X

• J-Global ID

  202401010770904154

• Researcher number

  51001739

• External link

  https://yuikasagi.com

researchmap URL

• https://researchmap.jp/yuikasagi

Research

Research Interests

• Brown dwarfs
• Exoplanets

Research Areas

• Natural sciences, Astronomy

Papers

• PyIRD: A Python-Based Data Reduction Pipeline for Subaru/IRD and REACH

  Yui Kasagi; Hajime Kawahara; Ziying Gu; Teruyuki Hirano; Takayuki Kotani; Masayuki Kuzuhara; Kento Masuda

  Journal of Open Source Software, 17 Jan. 2026, Peer-reviewed, Lead author

  
• Unveiling the Atmosphere of HR 7672 B from the Near-infrared High-resolution Spectrum Using REACH/Subaru

  Yui Kasagi; Yui Kawashima; Hajime Kawahara; Takayuki Kotani; Kento Masuda; Kyohoon Ahn; Olivier Guyon; Teruyuki Hirano; Nemanja Jovanovic; Masayuki Kuzuhara; Julien Lozi; Motohide Tamura; Taichi Uyama; Sebastien Vievard; Kenta Yoneta

  The Astronomical Journal, 01 Oct. 2025, Peer-reviewed, Lead author

  
• Atmospheric Retrieval of Subaru/IRD High-resolution Spectrum of the Archetype T-type Brown Dwarf Gl 229 B*

  Yui Kawashima; Hajime Kawahara; Yui Kasagi; Hiroyuki Tako Ishikawa; Kento Masuda; Takayuki Kotani; Tomoyuki Kudo; Teruyuki Hirano; Masayuki Kuzuhara; Stevanus K. Nugroho; John Livingston; Hiroki Harakawa; Jun Nishikawa; Masashi Omiya; Takuya Takarada; Motohide Tamura; Akitoshi Ueda

  The Astrophysical Journal, 20 Jul. 2025

  Access this paper :

  
• Differentiable Modeling of Planet and Substellar Atmosphere: High-resolution Emission, Transmission, and Reflection Spectroscopy with ExoJAX2

  Hajime Kawahara; Yui Kawashima; Shotaro Tada; Hiroyuki Tako Ishikawa; Ko Hosokawa; Yui Kasagi; Takayuki Kotani; Kento Masuda; Stevanus K. Nugroho; Motohide Tamura; Hibiki Yama; Daniel Kitzmann; Nicolas Minesi; Brett M. Morris

  The Astrophysical Journal, 01 Jun. 2025

  
• Weighing Single-lined Spectroscopic Binaries Using Tidal Effects on Radial Velocities: The Case of V723 Monocerotis

  Mio Tomoyoshi; Kento Masuda; Teruyuki Hirano; Yui Kasagi; Hajime Kawahara; Takayuki Kotani; Tomoyuki Kudo; Motohide Tamura; Sébastien Vievard

  The Astrophysical Journal, 01 Dec. 2024, Peer-reviewed

  
• Gliese 12 b: A Temperate Earth-sized Planet at 12 pc Ideal for Atmospheric Transmission Spectroscopy

  Masayuki Kuzuhara; Akihiko Fukui; John H. Livingston; José A. Caballero; Jerome P. de Leon; Teruyuki Hirano; Yui Kasagi; Felipe Murgas; Norio Narita; Masashi Omiya; Jaume Orell-Miquel; Enric Palle; Quentin Changeat; Emma Esparza-Borges; Hiroki Harakawa; Coel Hellier; Yasunori Hori; Kai Ikuta; Hiroyuki Tako Ishikawa; Takanori Kodama; Takayuki Kotani; Tomoyuki Kudo; Juan C. Morales; Mayuko Mori; Evangelos Nagel; Hannu Parviainen; Volker Perdelwitz; Ansgar Reiners; Ignasi Ribas; Jorge Sanz-Forcada; Bun’ei Sato; Andreas Schweitzer; Hugo M. Tabernero; Takuya Takarada; Taichi Uyama; Noriharu Watanabe; Mathias Zechmeister; Néstor Abreu García; Wako Aoki; Charles Beichman; Víctor J. S. Béjar; Timothy D. Brandt; Yéssica Calatayud-Borras; Ilaria Carleo; David Charbonneau; Karen A. Collins; Thayne Currie; John P. Doty; Stefan Dreizler; Gareb Fernández-Rodríguez; Izuru Fukuda; Daniel Galán; Samuel Geraldía-González; Josafat González-Garcia; Yuya Hayashi; Christina Hedges; Thomas Henning; Klaus Hodapp; Masahiro Ikoma; Keisuke Isogai; Shane Jacobson; Markus Janson; Jon M. Jenkins; Taiki Kagetani; Eiji Kambe; Yugo Kawai; Kiyoe Kawauchi; Eiichiro Kokubo; Mihoko Konishi; Judith Korth; Vigneshwaran Krishnamurthy; Takashi Kurokawa; Nobuhiko Kusakabe; Jungmi Kwon; Andrés Laza-Ramos; Florence Libotte; Rafael Luque; Alberto Madrigal-Aguado; Yuji Matsumoto; Dimitri Mawet; Michael W. McElwain; Pedro Pablo Meni Gallardo; Giuseppe Morello; Sara Muñoz Torres; Jun Nishikawa; Stevanus K. Nugroho; Masahiro Ogihara; Alberto Peláez-Torres; David Rapetti; Manuel Sánchez-Benavente; Martin Schlecker; Sara Seager; Eugene Serabyn; Takuma Serizawa; Monika Stangret; Aoi Takahashi; Huan-Yu Teng; Motohide Tamura; Yuka Terada; Akitoshi Ueda; Tomonori Usuda; Roland Vanderspek; Sébastien Vievard; David Watanabe; Joshua N. Winn; Maria Rosa Zapatero Osorio

  The Astrophysical Journal Letters, 01 Jun. 2024, Peer-reviewed

  
• Assessing Earth's atmospheric impact on near-infrared radial velocity measurements with IRD/Subaru

  Yui Kasagi; Takayuki Kotani; Teruyuki Hirano; Masayuki Kuzuhara; Masashi Omiya; Takuya Takarada; Hiroki Harakawa; Tomoyuki Kudo; Jun Nishikawa; Motohide Tamura; Bunei Sato

  GROUND-BASED AND AIRBORNE INSTRUMENTATION FOR ASTRONOMY X, 2024

  
• An Earth-sized Planet around an M5 Dwarf Star at 22 pc

  Teruyuki Hirano; Fei Dai; John H. Livingston; Sascha Grziwa; Kristine W. F. Lam; Yui Kasagi; Norio Narita; Hiroyuki Tako Ishikawa; Kohei Miyakawa; Luisa M. Serrano; Yuji Matsumoto; Eiichiro Kokubo; Tadahiro Kimura; Masahiro Ikoma; Joshua N. Winn; John P. Wisniewski; Hiroki Harakawa; Huan-Yu Teng; William D. Cochran; Akihiko Fukui; Davide Gandolfi; Eike W. Guenther; Yasunori Hori; Kai Ikuta; Kiyoe Kawauchi; Emil Knudstrup; Judith Korth; Takayuki Kotani; Vigneshwaran Krishnamurthy; Tomoyuki Kudo; Takashi Kurokawa; Masayuki Kuzuhara; Rafael Luque; Mayuko Mori; Jun Nishikawa; Masashi Omiya; Jaume Orell-Miquel; Enric Palle; Carina M. Persson; Seth Redfield; Eugene Serabyn; Alexis M. S. Smith; Aoi Takahashi; Takuya Takarada; Akitoshi Ueda; Vincent Van Eylen; Sébastien Vievard; Motohide Tamura; Bun’ei Sato

  The Astronomical Journal, 01 Mar. 2023, Peer-reviewed

  
• Dippers from TESS Full-frame Images. II. Spectroscopic Characterization of Four Young Dippers

  Yui Kasagi; Takayuki Kotani; Hajime Kawahara; Tomoyuki Tajiri; Takayuki Muto; Masataka Aizawa; Michiko S. Fujii; Kohei Hattori; Kento Masuda; Munetake Momose; Ryou Ohsawa; Satoshi Takita

  The Astrophysical Journal Supplement Series, 01 Apr. 2022, Peer-reviewed, Lead author

  
• Dippers from the TESS Full-frame Images. I. Results of the First One Year Data and Discovery of a Runaway Dipper

  Tomoyuki Tajiri; Hajime Kawahara; Masataka Aizawa; Michiko S. Fujii; Kohei Hattori; Yui Kasagi; Takayuki Kotani; Kento Masuda; Munetake Momose; Takayuki Muto; Ryou Ohsawa; Satoshi Takita

  The Astrophysical Journal Supplement Series, 23 Nov. 2020

  

External funds: Kakenhi

• 高精度視線速度測定で迫る褐色矮星の進化過程の解明

  Grant-in-Aid for Research Activity Start-up

  0204:Astronomy, earth and planetary science, and related fields

  Japan Aerospace EXploration Agency

  笠木 結

  From 31 Jul. 2024, To 31 Mar. 2026, Granted

  褐色矮星;系外惑星;光赤外線天文学;視線速度法

  https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-24K22912/

Education

Teaching subject(s)

• From 01 Apr. 2026, To 31 Mar. 2027

  Seminar on Theoretical Astrophysics A

  4026, Spring, Graduate School of Science, 1
• From 01 Apr. 2026, To 31 Mar. 2027

  Seminar on Theoretical Astrophysics D

  4029, Fall, Graduate School of Science, 1
• From 01 Apr. 2026, To 31 Mar. 2027

  Seminar on Theoretical Astrophysics C

  4028, Spring, Graduate School of Science, 1
• From 01 Apr. 2026, To 31 Mar. 2027

  Seminar on Theoretical Astrophysics B

  4027, Fall, Graduate School of Science, 1