High-velocity blueshifts of Hα and Fe XXV Heα lines during superflares of the RS CVn-type stars
Shun Inoue; Teruaki Enoto; Yuta Notsu; Hiroyuki Uchida; Kosuke Namekata; Hiroyuki Maehara; Satoshi Honda; Wataru Buz Iwakiri; Miki Kurihara; Masahiro Tsujimoto; Keiichi Namizaki; Takeshi Go Tsuru; Daisaku Nogami; Kazunari Shibata
Proceedings of the International Astronomical Union, 2024年12月
Multiwavelength Campaign Observations of a Young Solar-type Star, EK Draconis. III. Comparison between Starspot Mapping, Zeeman Doppler Imaging, and Multiwavelength Variability
Kai Ikuta; Kosuke Namekata; Pascal Petit; Vladimir S. Airapetian; Hiroyuki Maehara; Yuta Notsu; Aline A. Vidotto; Keith Gendreau; Sandra V. Jeffers; Stephen Marsden; Julien Morin; Coralie Neiner; Rishi R. Paudel; Daisaku Nogami; Kazunari Shibata
The Astrophysical Journal, 2026年04月02日
X-ray and H α superflare on an RS CVn-type star, UX Arietis: Constraint on the flare location from radial velocity change during the flare
Sota Urabe; Yohko Tsuboi; Kosuke Namekata; Sakura Nawa; Hiroyuki Maehara; Noboru Nemoto; Yuta Notsu; Wataru Iwakiri
Publications of the Astronomical Society of Japan, 2025年12月30日
Simultaneous Optical and Radio Observations of a Large Stellar Flare on EV Lac
A Semiempirical Estimate of Solar Extreme-ultraviolet Evolution from 10 Myr to 10 Gyr
Kevin France; Girish Duvvuri; Cynthia S. Froning; Alexander Brown; P. Christian Schneider; J. Sebastian Pineda; David Wilson; Allison Youngblood; Vladimir S. Airapetian; Kosuke Namekata; Yuta Notsu; Tristen Sextro
The Astronomical Journal, 2025年08月11日
Systematic NICER study of the low-ionized Fe Kα line on RS Canum Venaticorum-type stars
Shun Inoue; Teruaki Enoto; Yuta Notsu; Hiroyuki Uchida; Wataru Buz Iwakiri; Kosuke Namekata; Keith Gendreau
Monthly Notices of the Royal Astronomical Society, 2025年06月28日
High-time-cadence Spectroscopy and Photometry of Stellar Flares on M dwarf YZ Canis Minoris with the Seimei Telescope and TESS. I. Discovery of Rapid and Short-duration Prominence Eruptions
Rising Near-ultraviolet Spectra in Stellar Megaflares
Adam F. Kowalski; Rachel A. Osten; Yuta Notsu; Isaiah I. Tristan; Antigona Segura; Hiroyuki Maehara; Kosuke Namekata; Shun Inoue
The Astrophysical Journal, 2024年12月26日
Multiwavelength Campaign Observations of a Young Solar-type Star, EK Draconis. II. Understanding Prominence Eruption through Data-driven Modeling and Observed Magnetic Environment
Kosuke Namekata; Kai Ikuta; Pascal Petit; Vladimir S. Airapetian; Aline A. Vidotto; Petr Heinzel; Jiří Wollmann; Hiroyuki Maehara; Yuta Notsu; Shun Inoue; Stephen Marsden; Julien Morin; Sandra V. Jeffers; Coralie Neiner; Rishi R. Paudel; Antoaneta A. Avramova-Boncheva; Keith Gendreau; Kazunari Shibata
Assessing the capability of a model-based stellar XUV estimation
Munehito Shoda; Kosuke Namekata; Shinsuke Takasao
Astronomy & Astrophysics, 2024年11月08日
Multiwavelength Campaign Observations of a Young Solar-type Star, EK Draconis. I. Discovery of Prominence Eruptions Associated with Superflares
Kosuke Namekata; Vladimir S. Airapetian; Pascal Petit; Hiroyuki Maehara; Kai Ikuta; Shun Inoue; Yuta Notsu; Rishi R. Paudel; Zaven Arzoumanian; Antoaneta A. Avramova-Boncheva; Keith Gendreau; Sandra V. Jeffers; Stephen Marsden; Julien Morin; Coralie Neiner; Aline A. Vidotto; Kazunari Shibata
The Astrophysical Journal, 2024年01月01日
Temporal Variation of Flare Occurrence Rates via the Spot Evolution on the Sun and Solar-type Stars
Doppler imaging combined with high-cadence photometry
S. Lee; E. Bahar; H. V. Şenavcı; E. Işık; K. Ikuta; K. Namekata; H. Nagata; K. Kawauchi; M. Omiya; H. Izumiura; A. Tajitsu; B. Sato; S. Honda; D. Nogami
Astronomy & Astrophysics, 2026年03月02日
Discovery of multi-temperature coronal mass ejection signatures from a young solar analogue
Kosuke Namekata; Kevin France; Jongchul Chae; Vladimir S. Airapetian; Adam Kowalski; Yuta Notsu; Peter R. Young; Satoshi Honda; Soosang Kang; Juhyung Kang; Kyeore Lee; Hiroyuki Maehara; Kyoung-Sun Lee; Cole Tamburri; Tomohito Ohshima; Masaki Takayama; Kazunari Shibata
Nature Astronomy, 2025年10月27日
Do Young Suns Produce Frequent, Massive CMEs? Results from Five-year Dedicated Optical Observations of EK Draconis and V889 Hercules
Kosuke Namekata; Hiroyuki Maehara; Yuta Notsu; Satoshi Honda; Kai Ikuta; Daisaku Nogami; Kazunari Shibata
Time evolution of a white-light flare accompanied by probable postflare loops on the M-type dwarf EV Lacertae
Shinnosuke Ichihara; Daisaku Nogami; Kosuke Namekata; Hiroyuki Maehara; Yuta Notsu; Kai Ikuta; Satoshi Honda; Takato Otsu; Kazunari Shibata
Publications of the Astronomical Society of Japan, 2025年08月01日
High-time-cadence Spectroscopy and Photometry of Stellar Flares on M-dwarf YZ Canis Minoris with Seimei Telescope and TESS. II. Statistical Properties of Blue/Red Asymmetries in the Hα Line
Yuto Kajikiya; Kosuke Namekata; Yuta Notsu; Kai Ikuta; Hiroyuki Maehara; Bunei Sato; Daisaku Nogami
The Astrophysical Journal, 2025年05月20日
Multiwavelength observation of an active M-dwarf star EV Lacertae and its stellar flare accompanied by a delayed prominence eruption
Apache Point Observatory (APO)/SMARTS Flare Star Campaign Observations. I. Blue Wing Asymmetries in Chromospheric Lines during Mid-M-Dwarf Flares from Simultaneous Spectroscopic and Photometric Observation Data
Yuta Notsu; Adam F. Kowalski; Hiroyuki Maehara; Kosuke Namekata; Kenji Hamaguchi; Teruaki Enoto; Isaiah I. Tristan; Suzanne L. Hawley; James R. A. Davenport; Satoshi Honda; Kai Ikuta; Shun Inoue; Keiichi Namizaki; Daisaku Nogami; Kazunari Shibata
The Astrophysical Journal, 2024年01月25日
Magnitude Estimates for the Carrington Flare in 1859 September: As Seen from the Original Records
Hisashi Hayakawa; Sabrina Bechet; Frédéric Clette; Hugh S. Hudson; Hiroyuki Maehara; Kosuke Namekata; Yuta Notsu
The Astrophysical Journal Letters, 2023年08月29日
Starspot Mapping with Adaptive Parallel Tempering. II. Application to TESS Data for M-dwarf Flare Stars AU Microscopii, YZ Canis Minoris, and EV Lacertae
Kai Ikuta; Kosuke Namekata; Yuta Notsu; Hiroyuki Maehara; Soshi Okamoto; Satoshi Honda; Daisaku Nogami; Kazunari Shibata
Universal Scaling Laws for Solar and Stellar Atmospheric Heating: Catalog of Power-law Index between Solar Activity Proxies and Various Spectral Irradiances
Shin Toriumi; Vladimir Airapetian; Kosuke Namekata; Yuta Notsu
The Astrophysical Journal Supplement Series, 2022年10月01日
Sun-as-a-star Analysis of Hα Spectra of a Solar Flare Observed by SMART/SDDI: Time Evolution of Red Asymmetry and Line Broadening
Kosuke Namekata; Kiyoshi Ichimoto; Takako T. Ishii; Kazunari Shibata
The Astrophysical Journal, 2022年07月01日
The Atmospheric Response to High Nonthermal Electron-beam Fluxes in Solar Flares. II. Hydrogen-broadening Predictions for Solar Flare Observations with the Daniel K. Inouye Solar Telescope
Adam Kowalski; Joel Allred; Mats Carlsson; Graham S. Kerr; Pier-Emmanuel Tremblay; Kosuke Namekata; David Kuridze; Han Uitenbroek
The Astrophysical Journal, 2022年04月01日
Discovery of a Long-duration Superflare on a Young Solar-type Star EK Draconis with Nearly Similar Time Evolution for Hα and White-light Emissions
Spectroscopic and photometric observations of dwarf nova superoutbursts by the 3.8 m telescope Seimei and the Variable Star Network
Yusuke Tampo; Keisuke Isogai; Naoto Kojiguchi; Hiroyuki Maehara; Kenta Taguchi; Taichi Kato; Mariko Kimura; Yasuyuki Wakamatsu; Masaaki Shibata; Daisaku Nogami; Miho Kawabata; Keiichi Maeda; Kosuke Namekata; Soshi Okamoto; Masaaki Otsuka; Umut Burgaz; Shumpei Nagoshi; Hiroshi Itoh; Tonny Vanmunster; Tamás Tordai; Geoffrey Stone; Katsura Matsumoto; Daiti Fujii; Ryota Matsumura; Momoka Nakagawa; Nodoka Takeuchi; Yuki Zenkou; Elena P Pavlenko; Kirill A Antonyuk; Nikolaj V Pit; Oksana I Antonyuk; Julia V Babina; Aleksei V Baklanov; Aleksei A Sosnovskij; Sergey Yu Shugarov; Nataly Katysheva; Drahomír Chochol; Shawn Dvorak; Pavol A Dubovsky; Tomáš Medulka; Igor Kudzej; Seiichiro Kiyota; Alexandra M Zubareva; Alexandr A Belinski; Natalia P Ikonnikova; Marina A Burlak; Yasuo Sano; Masanori Mizutani; Javier Ruiz; Roger D. Pickard; Franz-Josef Hambsch
Publications of the Astronomical Society of Japan, 2021年06月13日
Time-resolved spectroscopy and photometry of M dwarf flare star YZ Canis Minoris with OISTER and TESS: Blue asymmetry in the Hα line during the non-white light flare
Hiroyuki Maehara; Yuta Notsu; Kosuke Namekata; Satoshi Honda; Adam F Kowalski; Noriyuki Katoh; Tomohito Ohshima; Kota Iida; Motoki Oeda; Katsuhiro L Murata; Masayuki Yamanaka; Kengo Takagi; Mahito Sasada; Hiroshi Akitaya; Kai Ikuta; Soshi Okamoto; Daisaku Nogami; Kazunari Shibata
Publications of the Astronomical Society of Japan, 2021年02月05日
Statistical Properties of Superflares on Solar-type Stars: Results Using All of the Kepler Primary Mission Data
Soshi Okamoto; Yuta Notsu; Hiroyuki Maehara; Kosuke Namekata; Satoshi Honda; Kai Ikuta; Daisaku Nogami; Kazunari Shibata
The Astrophysical Journal, 2021年01月11日
Starspot Mapping with Adaptive Parallel Tempering. I. Implementation of Computational Code
Kai Ikuta; Hiroyuki Maehara; Yuta Notsu; Kosuke Namekata; Taichi Kato; Shota Notsu; Soshi Okamoto; Satoshi Honda; Daisaku Nogami; Kazunari Shibata
The Astrophysical Journal, 2020年10月13日
Optical and X-ray observations of stellar flares on an active M dwarf AD Leonis with the Seimei Telescope, SCAT, NICER, and OISTER
Kosuke Namekata; Hiroyuki Maehara; Ryo Sasaki; Hiroki Kawai; Yuta Notsu; Adam F Kowalski; Joel C Allred; Wataru Iwakiri; Yohko Tsuboi; Katsuhiro L Murata; Masafumi Niwano; Kazuki Shiraishi; Ryo Adachi; Kota Iida; Motoki Oeda; Satoshi Honda; Miyako Tozuka; Noriyuki Katoh; Hiroki Onozato; Soshi Okamoto; Keisuke Isogai; Mariko Kimura; Naoto Kojiguchi; Yasuyuki Wakamatsu; Yusuke Tampo; Daisaku Nogami; Kazunari Shibata
Publications of the Astronomical Society of Japan, 2020年08月01日
Temporal Evolution of Spatially Resolved Individual Star Spots on a Planet-hosting Solar-type Star: Kepler-17
Kosuke Namekata
Institute of Physics Publishing IOP, 2020年03月
Impact of Stellar Superflares on Planetary Habitability
Yosuke Yamashiki; Hiroyuki Maehara; Vladimir Airapetian; Yuta Notsu; Tatsuhiko Sato; Shota Notsu; Ryusuke Kuroki; Keiya Murashima; Hiroaki Sato; Kosuke Namekata; Takanori Sasaki; Thomas B. Scott; Hina Bando; Subaru Nashimoto; Fuka Takagi; Cassandra Ling; Daisaku Nogami; Kazunari Shibata
The Astrophysical Journal, 2019年08月20日
Do Kepler Superflare Stars Really Include Slowly Rotating Sun-like Stars?—Results Using APO 3.5 m Telescope Spectroscopic Observations and Gaia-DR2 Data
Yuta Notsu; Hiroyuki Maehara; Satoshi Honda; Suzanne L. Hawley; James R. A. Davenport; Kosuke Namekata; Shota Notsu; Kai Ikuta; Daisaku Nogami; Kazunari Shibata
UV, X-Ray, and Gamma-Ray Space Instrumentation for Astronomy XXIV, 2025年09月29日
The Exospace Weather Frontier
R. O. P. Loyd; E. L. Shkolnik; J. Lazio; G. W. Hallinan; J. Alvarado-Gómez; L. Amaral; I. Davis; A. Farrish; J. Green; D. Brain; B. Chen; C. Cohen; S. Curry; K. Dissauer; A. Egan; N. Gopalswamy; N. Gronoff; S. Habbal; R. Hu; M. Jin; J. P. Mason; R. Murray-Clay; K. Namekata; R. Osten; A. Segura; A. Veronig; A. Vidotto; M. Wilson; Y. Xu
Report prepared for the W. M. Keck Institute for Space Studies (KISS), California Institute of Technology, 2025年, 招待有り
Overview of the LAPYUTA mission (Life-environmentology, Astronomy, and PlanetarY Ultraviolet Telescope Assembly)
せいめい望遠鏡観測提案 審査員, XRISM観測提案 審査員, DiRAC計算資源配分提案 審査員, National Science Centre, Poland 研究費申請 審査員
査読
Cool Stars 23
企画立案・運営等
自 2026年06月, 至 2026年06月
IAU Symposium 400 SOC
企画立案・運営等, パネル司会・セッションチェア等
自 2025年07月21日, 至 2025年07月25日
Stellar magnetic activity workshop 2024 Chair
企画立案・運営等, パネル司会・セッションチェア等
自 2024年02月29日, 至 2024年03月01日
EAS 2023 Symposium S13 SOC
企画立案・運営等
自 2023年07月10日, 至 2023年07月14日
Stellar magnetic activity workshop 2022 Chair
企画立案・運営等, パネル司会・セッションチェア等
自 2022年05月12日, 至 2022年05月12日
Nature, Nature Astronomy, National Science Review, Scientific Reports, ApJ, AJ, ApJS, ApJL, A&A, PASJ, MNRAS, Solar Physics, Journal of High Energy Astrophysics