340 citations · 3.2k across the 80 of their papers we have counts for
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Starspots, chromospheric emission lines, and flares of zero-age main-sequence stars
Mai Yamashita, Yoichi Itoh, Yumiko Oasa
Zero-age main-sequence (ZAMS) stars are considered to have enormous starspots and show strong chromospheric emission lines because of their strong surface magnetic field. We discus…
Measurements of Chromospheric Mg I Emission Lines of Zero-Age Main-Sequence Stars
Mai Yamashita, Yoichi Itoh
The chromosphere is the active atmosphere in which energetic eruption events, such as flares, occur. Chromospheric activity is driven by the magnetic field generated by stellar rot…
Rotation-Activity Relation of Ca II and Mg I Infrared Emission Lines of Young Stars
Mai Yamashita, Yoichi Itoh, Yuhei Takagi
To reveal the detail of the internal structure, the relationship between chromospheric activity and the Rossby number, N_R (= rotational period P / convective turnover time tau_c),…
Revealing the spectroscopic variations of FU Orionis object V960 Mon with high-resolution spectroscopy
Yuhei Takagi, Satoshi Honda, Akira Arai +3
We present the results of the high-resolution spectroscopy of the FU Orionis-type star V960 Mon. The brightness of V960 Mon decreased continuously after the outburst was detected i…
Measurements of the Ca II infrared triplet emission lines of pre-main-sequence stars
Mai Yamashita, Yoichi Itoh, Yuhei Takagi
We investigated the chromospheric activity of 60 pre-main-sequence (PMS) stars in four molecular clouds and five moving groups. It is considered that strong chromospheric activity…
High-Resolution Spectroscopy of Winds Associated with T Tauri Stars
Naoto Iguchi, Yoichi Itoh
We carried out optical high-resolution spectroscopy of T Tauri stars using the Subaru Telescope. Using archived data from the Keck Telescope and the Very Large Telescope, we detect…