Shotaro Tada

About

Research interests: Exoplanets, astronomical instrumentation
Hobbies: Karate, working out
Message: Please feel free to contact me if you have any questions or are interested in collaboration.

Affiliation: Institute of Space and Astronautical Science (ISAS), JAXA
Position: Aerospace Project Research Associate
Email: tada[at]ir.isas.jaxa.jp (replace [at] with @)
GitHub: sh-tada
ORCID: 0000-0002-4093-8736

Research

My research focuses on exoplanet characterization and astronomical instrumentation.

Atmospheric inhomogeneities revealed by transit observations

I developed a method to investigate horizontal inhomogeneities in exoplanet atmospheres using transit spectroscopy. By measuring wavelength-dependent changes in transit timing, duration, and depth, this approach compares the atmospheric properties at the morning and evening limbs as well as regions slightly offset from the terminator.

トランジット観測を用いて、系外惑星大気の水平方向の非一様性を調べる手法を開発した。波長ごとのトランジット時刻・継続時間・深さから、朝夕のリムや昼夜境界付近の大気特性の違いを読み解き、大気循環や光化学反応の影響を探る。

Related work: Tada et al. 2025; Kawahara et al. 2025

Information content of light curves for non-circular planetary silhouettes

I studied what information a transit light curve contains when the projected silhouette of a planet is not circular. By interpreting ingress and egress as Radon-transform measurements, this work clarifies which components of the two-dimensional attenuation map can be constrained and which remain degenerate.

惑星のシルエットが円形とは限らない場合に、トランジットライトカーブから形状情報をどこまで引き出せるかを調べた。 Ingress/Egressをラドン変換として捉えることで、観測から制約できる成分や、形状情報と軌道パラメータとの縮退などについて整理した。

Related work: Tada, submitted

Infrared detector development for the JASMINE mission

I work on the development and characterization of infrared detectors for the JASMINE mission, which requires high-precision near-infrared astrometry and photometry. My work includes InGaAs sensor performance tests, characterization-method development, and environmental testing for operation in space.

JASMINEミッションに向けて、近赤外線検出器の開発・性能評価に取り組んでいる。 InGaAsセンサーの低温性能評価、精密な較正手法の開発、宇宙環境での動作を確認するための環境試験などを行っている。

Related work: Miyakawa et al. 2024; Tada et al. in prep.

Publications

See full list on: NASA ADS (full list)

Selected Publications

First-author

Journal Article · Peer-reviewed Shotaro Tada, Hajime Kawahara, Yui Kawashima, Takayuki Kotani, Kento Masuda, “Probing Two-dimensional Asymmetries of an Exoplanet Atmosphere from Chromatic Transit Variation,” The Astronomical Journal, 169, 255, 2025. doi

Co-authored

Journal Article · Peer-reviewed 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, “Differentiable Modeling of Planet and Substellar Atmosphere,” The Astrophysical Journal, 985, 263, 2025. doi
Conference Proceedings · Non-peer-reviewed Kohei Miyakawa, Shotaro Tada, Hirokazu Kataza, Ryouhei Kano, Takehiko Wada, Masanobu Ozaki, Takayuki Kotani, Hajime Kawahara, Fumihiko Usui, Yui Kasagi, “Performance report of a substrate-removed InGaAs sensor for the JASMINE mission,” Proc. SPIE, 13103, 2024. doi

Talks

Recent Talks

International Conferences

Shotaro Tada, Kohei Miyakawa, Hirokazu Kataza, Iona Kondo, Fumihiko Usui, Yui Kasagi, Hajime Kawahara, Takehiko Wada, Ryouhei Kano, Masanobu Ozaki, Takayuki Kotani and JASMINE team, “Development of an InGaAs infrared detector for the JASMINE mission,” Scientific Detector Workshop, Australian National University, October 2025. Oral presentation.

Domestic Conferences

Shotaro Tada, Kohei Miyakawa, Hirokazu Kataza, Fumihiko Usui, Iona Kondo, Hajime Kawahara, Yui Kasagi, Takehiko Wada, Ryouhei Kano, Masanobu Ozaki, Takayuki Kotani, Ko Hosokawa, Yuji Sakamoto and JASMINE team, “JASMINE搭載検出器の開発状況: 2Kx2K画素素子の低温性能評価,” 日本天文学会2026年春季年会, V202a, Kyoto Sangyo University, March 2026. Oral presentation.
Shotaro Tada, “トランジットから惑星形状はどこまで分かるか,” 系外惑星大気ワークショップFY2025, Ritsumeikan University, March 2026. Oral presentation.
Shotaro Tada, “系外惑星大気の水平非一様性の推定,” CPS/WTK & ABC ワークショップ『系外惑星表層環境の観測とモデリング』, Center for Planetary Science (CPS), February 2026. Invited oral presentation.
Shotaro Tada, Kohei Miyakawa, Hirokazu Kataza, Fumihiko Usui, Iona Kondo, Hajime Kawahara, Yui Kasagi, Takehiko Wada, Ryouhei Kano, Masanobu Ozaki, Ko Hosokawa, Takayuki Kotani, Yuji Sakamoto and JASMINE team, “JASMINEに向けたInGaAs赤外線検出器の環境試験,” 第19回可視赤外線観測装置技術ワークショップ, Kyoto Sangyo University, November 2025. Oral presentation.
Shotaro Tada, Hajime Kawahara, Yui Kawashima, Takayuki Kotani, Kento Masuda, “トランジット光度曲線の波長依存性から探る系外惑星大気の非一様性,” 2025年度光赤天連シンポジウム, キャンパスプラザ京都, November 2025. Oral presentation.
Shotaro Tada, Hajime Kawahara, Yui Kawashima, Takayuki Kotani, Kento Masuda, “Probing Two-dimensional Asymmetries of an Exoplanet Atmosphere from Chromatic Transit Variation,” 日本天文学会2025年秋季年会, Z104a, 海峡メッセ下関, September 2025. Oral presentation.

Past Talks

International Conferences

Domestic Conferences

Shotaro Tada, Hajime Kawahara, Yui Kawashima, Takayuki Kotani, Kento Masuda, “JWSTによる透過光分光データが示す系外惑星大気の非一様性,” JASMINE Consortium Meeting, National Astronomical Observatory of Japan, August 2024. Oral presentation.
Shotaro Tada, Takayuki Kotani, Ryouhei Kano, Kohei Miyakawa, Hirokazu Kataza, Hajime Kawahara, Takehiko Wada, Fumihiko Usui, Naoteru Gouda, “Development of detector calibration techniques for planet search with JASMINE,” Japan Geoscience Union Meeting 2023, PEM11-21, Makuhari Messe, May 2023. Oral presentation.
Shotaro Tada, Takayuki Kotani, Hirokazu Kataza, Takehiko Wada, Hajime Kawahara, Fumihiko Usui, Naoki Gouda, Ryouhei Kano, Kohei Miyakawa and JASMINE team, “JASMINEでの精密測光・位置天文に向けた検出器の新しい較正手法の開発,” 日本天文学会2023年春季年会, V250a, Rikkyo University, March 2023. Oral presentation.
Shotaro Tada, Takayuki Kotani, Hirokazu Kataza, Takehiko Wada, Hajime Kawahara, Fumihiko Usui, Ryouhei Kano, Kohei Miyakawa, Naoki Gouda and JASMINE team, “JASMINEでの精密測光・位置天文に向けた検出器特性の較正手法の開発,” 第23回宇宙科学シンポジウム, P-100, Online, January 2023. Poster presentation.
Shotaro Tada, Takayuki Kotani, Hirokazu Kataza, Takehiko Wada, Hajime Kawahara, Fumihiko Usui, Ryouhei Kano, Kohei Miyakawa, Naoki Gouda and JASMINE team, “JASMINEでの精密測光・位置天文に向けた新しいフラット補正技術と検出器特性精密測定方法の開発,” 第11回可視赤外線観測装置技術ワークショップ, Kyoto University, December 2022. Oral presentation.
Shotaro Tada, Takayuki Kotani, Hirokazu Kataza, Takehiko Wada, Fumihiko Usui, Naoki Gouda, Ryouhei Kano, Kohei Miyakawa, Hajime Kawahara and JASMINE team, “JASMINEでの精密測光・位置天文に向けた新しいフラット補正技術と検出器特性精密測定方法の開発,” 日本天文学会2022年秋季年会, Z222a, Online, September 2022. Oral presentation.
Shotaro Tada, Takayuki Kotani, Yutaka Hayano, Yosuke Minowa, “可視シングルモードファイバー高分散分光器に向けた高効率ファイバー入射光学系の開発,” 日本天文学会2022年春季年会, V208a, Online, March 2022. Oral presentation.
Shotaro Tada, Takayuki Kotani, Yutaka Hayano, Yosuke Minowa, “可視シングルモードファイバー高分散分光器に向けた高効率ファイバー入射光学系の開発,” 第10回可視赤外線観測装置技術ワークショップ, Online, December 2021. Oral presentation.

CV

Position

Apr 2025 - Present: Aerospace Project Research Associate, Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA)

Education

Apr 2020 - Mar 2025: Ph.D. in Astronomical Science, School of Physical Sciences, SOKENDAI (The Graduate University for Advanced Studies)
Apr 2016 - Mar 2020: B.Sc. in Earth and Planetary Physics, Faculty of Science, The University of Tokyo

Grants

KAKENHI Grant-in-Aid for Research Activity Start-up, Project No. 25K23414, Principal Investigator, 2025-2027. Project: “系外惑星大気における光化学反応の役割の解明”