radiation mechanisms: general;
stars: individual: is an element of Eridani;
radio continuum: stars;
CORONAL MASS EJECTIONS;
EPSILON ERIDANI;
LOSS RATES;
STARS;
AGE;
D O I:
10.1051/0004-6361/202347156
中图分类号:
P1 [天文学];
学科分类号:
0704 ;
摘要:
Some solar-type stars are known to present faint, time-variable radio continuum emission whose nature is not clearly established. We report on Jansky Very Large Array observations of the nearby star is an element of Eridani at 10.0 and 33.0 GHz. We find that this star has flux density variations on scales down to days, hours, and minutes. On 2020 April 15 it exhibited a radio pulse at 10.0 GHz with a total duration of about 20 min and a peak four times larger than the plateau of 40 mu Jy present in that epoch. We were able to model the time behavior of this radio pulse in terms of the radiation from shocks ramming into the stellar wind. Such shocks can be produced by the wind interaction of violently expanding gas heated suddenly by energetic electrons from a stellar flare, similar to the observed solar flares. Because of the large temperature needed in the working surface to produce the observed emission, this has to be nonthermal. It could be gyrosynchrotron or synchrotron emission. Unfortunately, the spectral index or polarization measurements from the radio pulse do not have a high enough signal-to-noise ratio to allow us to determine its nature.
机构:
Kumamoto Univ, Grad Sch Sci & Technol, Kumamoto 8608555, JapanKumamoto Univ, Grad Sch Sci & Technol, Kumamoto 8608555, Japan
Shiohira, Yuta
Terada, Yuka
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机构:
Univ Tokyo, Grad Sch Sci, Dept Astron, Tokyo 1130033, JapanKumamoto Univ, Grad Sch Sci & Technol, Kumamoto 8608555, Japan
Terada, Yuka
Mukuno, Den
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机构:
Kumamoto Univ, Grad Sch Sci & Technol, Kumamoto 8608555, JapanKumamoto Univ, Grad Sch Sci & Technol, Kumamoto 8608555, Japan
Mukuno, Den
Fujii, Yuka
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机构:
Natl Astron Observ Japan, Tokyo 1818588, Japan
Tokyo Inst Technol, Earth Life Sci Inst, Tokyo 1528550, JapanKumamoto Univ, Grad Sch Sci & Technol, Kumamoto 8608555, Japan
Fujii, Yuka
Takahashi, Keitaro
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机构:
Kumamoto Univ, Grad Sch Sci & Technol, Kumamoto 8608555, Japan
Kumamoto Univ, Int Res Org Adv Sci & Technol, Kumamoto 8608555, JapanKumamoto Univ, Grad Sch Sci & Technol, Kumamoto 8608555, Japan