Email: Yuta.Notsu_at_colorado.edu   (Please replace "_at_" with "@".) 

(Other webpages: @LASP    @ CU/APS    @CU Experts    @Google Scholar )

Laboratory for Atmospheric and Space Physics (LASP),  University of Colorado Boulder (CU Boulder)

National Solar Observatory (NSO)

I am studying stellar magnetic activities especially "superflares" on solar-type (G-type) stars and cooler K,M-type stars, using the various photometric and spectroscopic data from space and ground telescopes (e.g., Kepler, TESS, APO3.5m, SMARTS1.5m, NICER).  Through these observational studies, I investigate how frequently superflares occur on G,K,M-type stars, how large superflare events occur in the stellar atmosphere (photosphere - choromosphere - corona), and how planets (e.g., Earth, Mars, exoplanets) are affected from these flares.  

[Recent News] 

(Nov 3, 2023) A new review paper I joined “Extreme Solar Events: Setting up a Paradigm" (Usoskin, Miyake, et al.) is published in Space Science Review. This review is based on our joint work of the International Space Science Institute (ISSI) team #510 (2020–2022) .

(Oct 4, 2023) Our new paper is accepted for The Astrophysical Journal and is available in the arXiv: "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"   

                                 Update: Published (Notsu et al. 2024, ApJ, 961, 189) on January 25, 2024 

(Feb 27, 2023) Press release on our new paper (Inoue et al.)    (English) "Superflare with Massive, High-Velocity Prominence Eruption "  (日本語🇯🇵)「史上最大質量の超高速恒星プロミネンス噴出―せいめい望遠鏡が捉えた極限宇宙天気現象― 」

(Feb 14, 2023) Our new paper (Namizaki et al.) is featured at astrobites "Asymmetries are red, violets are blue, superflares are seen in white light, and H-alpha too!"

(Feb 3, 2023) Our new text book on “Solar-Terrestrial Environmental Prediction” is now published  ! I contributed Section 11 "Explorations of Extreme Space Weather Events from Stellar Observations and Archival Investigations"

I contributed to Section 11 "Explorations of Extreme Space Weather Events from Stellar Observations and Archival Investigations".

(July 4, 2022) Invited talk in the splinter session of Coolstars 21 "Solar and stellar coronal mass ejections"

(June 7 - 10, 2022) 2nd team meeting of our ISSI team "Solar Extreme Events: Setting Up a Paradigm"  

(Dec 9, 2021) Our paper (Namekata et al.) is published in Nature Astronomy !      Press Release 🇺🇸 "A young, sun-like star may hold warnings for life on Earth" (CU Boulder),   🇯🇵 「太陽型星のスーパーフレアから噴出する巨大フィラメントを初検出 —昔の、そして今の惑星環境や文明に与える脅威— 」(国立天文台)

(Oct 16, 2021) 京一中150周年洛北高校70周年記念式典  記念講演「宇宙への誘い」にて、「観測で迫るスーパーフレアの謎」という講演を行いました。(Youtube配信 (記念講演は1時間40分頃から))

(Sep 27 - Oct 1, 2021) The 1st team meeting of our ISSI team "Solar Extreme Events: Setting Up a Paradigm"   (I joined remotely)

(August 8, 2021) 太陽地球圏環境予測 オープン・テキストブック (PSTEP Open Textbook) 公開   (「3-4-1.太陽型星のスーパーフレア (3-4.超巨大フレアと極端宇宙天気現象の可能性)」を執筆担当)

(Apr 1, 2021) From this April, my formal position has been slightly changed. While I still live in Boulder and work at LASP and NSO, I’m also affiliated with exoplanet group in Tokyo Tech as JSPS fellow (PD). I'm looking forward more collaborations with exoplanet researchers.

(Feb 1, 2021) Invited talk at COSPAR2021 Session E2.1-0026-21 MAGNETIC FLUX ROPES IN SOLAR AND STELLAR ENVIRONMENTS: Pre-recorded talk (Youtube) is available: "Superflares investigated with Kepler&TESS photometric data and recent multi-wavelength campaign observations"

(June 10, 2020) Press release :   🇯🇵「京大せいめい望遠鏡でスーパーフレアの検出に成功 －生命居住可能な惑星への影響の理解に向けて－」(京都大学Webpage)      (国立天文台Webpage)    (English) "The Lion’s Roar: New Telescope Spots Superflare in Leo" (Kyoto Univ)      (See also NAOJ page)

(June 7, 2020) Some of our research is featured in Kurzgesagt movie "Could Solar Storms Destroy Civilization? Solar Flares & Coronal Mass Ejections"  (cf.   Sources & further reading)

(Oct 7 - 11, 2019)  The 1st team meeting of our ISSI team "The Role Of Solar And Stellar Energetic Particles On (Exo)Planetary Habitability (ETERNAL)" led by K. Herbst (DE) & J.L. Grenfell (DE) 

(July 16, 2019) 🇯🇵 生命が居住可能な系外惑星へのスーパーフレアの影響を算出 －ハビタブル惑星における宇宙線被ばくの定量化に成功－ (京都大学Webpage)   (🇯🇵JAEA  Webpage ,  🇯🇵 国立天文台 Webpage)

(June 10, 2019) 🇺🇸Press Release at AAS234 from CU Boulder "Rare ‘superflares’ could one day threaten Earth"        (🇯🇵日本語記事＠京都大学Webpage)