A Superflare on YZ Canis Minoris Observed by the Seimei Telescope and TESS: Red Asymmetry of Hα Emission Associated with White-light Emission
Active M-type stars are known to often produce superflares on the surface. Radiation from stellar (super)flares is important for exoplanet habitability, but the mechanisms are not well understood. In this paper, we report simultaneous optical spectroscopic and photometric observations of a stellar s...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/acb928 |
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| author | Keiichi Namizaki Kosuke Namekata Hiroyuki Maehara Yuta Notsu Satoshi Honda Daisaku Nogami Kazunari Shibata |
| author_facet | Keiichi Namizaki Kosuke Namekata Hiroyuki Maehara Yuta Notsu Satoshi Honda Daisaku Nogami Kazunari Shibata |
| author_sort | Keiichi Namizaki |
| collection | DOAJ |
| description | Active M-type stars are known to often produce superflares on the surface. Radiation from stellar (super)flares is important for exoplanet habitability, but the mechanisms are not well understood. In this paper, we report simultaneous optical spectroscopic and photometric observations of a stellar superflare on an active M dwarf, YZ Canis Minoris, with the 3.8 m Seimei telescope and the Transiting Exoplanet Survey Satellite. The flare bolometric energy is ${1.3}_{-0.6}^{+1.6}\times {10}^{34}\,\mathrm{erg}$ and the H α energy is ${3.0}_{-0.1}^{+0.1}\times {10}^{32}\,\mathrm{erg}$ . The H α emission line profile shows red asymmetry throughout the flare, with a duration of 4.6–5.1 hr. The velocity of the red asymmetry is ∼200–500 km s ^–1 and the line width of H α broadens up to 34 ± 14 Å. The redshifted velocity and line width of H α line decay more rapidly than the equivalent width, and their time evolutions are correlated with that of the white-light emission. This indicates the possibility of the white light, the H α red asymmetry, and the H α line broadening originating from nearly the same site, i.e., the dense chromospheric condensation region, heated by nonthermal electrons. On the other hand, the flux ratio of the redshifted excess components to the central components is enhanced one hr after the flare’s onset. This may be due to the main source of the red asymmetry changing to post-flare loops in the later phase of the flare. |
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| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-12T03:16:39Z |
| publishDate | 2023-01-01 |
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| series | The Astrophysical Journal |
| spelling | doaj.art-02671677cf674e30abb4a573b63d80c12023-09-03T14:08:32ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-0194516110.3847/1538-4357/acb928A Superflare on YZ Canis Minoris Observed by the Seimei Telescope and TESS: Red Asymmetry of Hα Emission Associated with White-light EmissionKeiichi Namizaki0Kosuke Namekata1https://orcid.org/0000-0002-1297-9485Hiroyuki Maehara2https://orcid.org/0000-0003-0332-0811Yuta Notsu3https://orcid.org/0000-0002-0412-0849Satoshi Honda4https://orcid.org/0000-0001-6653-8741Daisaku Nogami5https://orcid.org/0000-0001-9588-1872Kazunari Shibata6https://orcid.org/0000-0003-1206-7889Department of Astronomy, Kyoto University , Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan ; namizaki@kusastro.kyoto-u.ac.jpALMA Project , NAOJ, NINS, Osawa, Mitaka, Tokyo 181-8588, JapanOkayama Branch Office , Subaru Telescope, NAOJ, NINS, Kamogata, Asakuchi, Okayama 719-0232, JapanLaboratory for Atmospheric and Space Physics, University of Colorado Boulder , 3665 Discovery Drive, Boulder, CO 80303, USA; National Solar Observatory , 3665 Discovery Drive, Boulder, CO 80303, USA; Department of Earth and Planetary Sciences, Tokyo Institute of Technology , 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, JapanNishi-Harima Astronomical Observatory, Center for Astronomy, University of Hyogo , Sayo, Hyogo 679-5313, JapanDepartment of Astronomy, Kyoto University , Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan ; namizaki@kusastro.kyoto-u.ac.jp; Astronomical Observatory, Kyoto University , Sakyo, Kyoto 606-8502, JapanKwasan Observatory, Kyoto University , Yamashina, Kyoto 607-8471, Japan; School of Science and Engineering, Doshisha University , Kyotanabe, Kyoto 610-0321, JapanActive M-type stars are known to often produce superflares on the surface. Radiation from stellar (super)flares is important for exoplanet habitability, but the mechanisms are not well understood. In this paper, we report simultaneous optical spectroscopic and photometric observations of a stellar superflare on an active M dwarf, YZ Canis Minoris, with the 3.8 m Seimei telescope and the Transiting Exoplanet Survey Satellite. The flare bolometric energy is ${1.3}_{-0.6}^{+1.6}\times {10}^{34}\,\mathrm{erg}$ and the H α energy is ${3.0}_{-0.1}^{+0.1}\times {10}^{32}\,\mathrm{erg}$ . The H α emission line profile shows red asymmetry throughout the flare, with a duration of 4.6–5.1 hr. The velocity of the red asymmetry is ∼200–500 km s ^–1 and the line width of H α broadens up to 34 ± 14 Å. The redshifted velocity and line width of H α line decay more rapidly than the equivalent width, and their time evolutions are correlated with that of the white-light emission. This indicates the possibility of the white light, the H α red asymmetry, and the H α line broadening originating from nearly the same site, i.e., the dense chromospheric condensation region, heated by nonthermal electrons. On the other hand, the flux ratio of the redshifted excess components to the central components is enhanced one hr after the flare’s onset. This may be due to the main source of the red asymmetry changing to post-flare loops in the later phase of the flare.https://doi.org/10.3847/1538-4357/acb928Stellar flaresStellar phenomenaOptical flaresSolar flaresMagnetic variable starsM dwarf stars |
| spellingShingle | Keiichi Namizaki Kosuke Namekata Hiroyuki Maehara Yuta Notsu Satoshi Honda Daisaku Nogami Kazunari Shibata A Superflare on YZ Canis Minoris Observed by the Seimei Telescope and TESS: Red Asymmetry of Hα Emission Associated with White-light Emission The Astrophysical Journal Stellar flares Stellar phenomena Optical flares Solar flares Magnetic variable stars M dwarf stars |
| title | A Superflare on YZ Canis Minoris Observed by the Seimei Telescope and TESS: Red Asymmetry of Hα Emission Associated with White-light Emission |
| title_full | A Superflare on YZ Canis Minoris Observed by the Seimei Telescope and TESS: Red Asymmetry of Hα Emission Associated with White-light Emission |
| title_fullStr | A Superflare on YZ Canis Minoris Observed by the Seimei Telescope and TESS: Red Asymmetry of Hα Emission Associated with White-light Emission |
| title_full_unstemmed | A Superflare on YZ Canis Minoris Observed by the Seimei Telescope and TESS: Red Asymmetry of Hα Emission Associated with White-light Emission |
| title_short | A Superflare on YZ Canis Minoris Observed by the Seimei Telescope and TESS: Red Asymmetry of Hα Emission Associated with White-light Emission |
| title_sort | superflare on yz canis minoris observed by the seimei telescope and tess red asymmetry of hα emission associated with white light emission |
| topic | Stellar flares Stellar phenomena Optical flares Solar flares Magnetic variable stars M dwarf stars |
| url | https://doi.org/10.3847/1538-4357/acb928 |
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