MAXI/GSC detection of a possible X-ray flare from an active binary star BY Dra
ATel #6042; M. Serino (RIKEN), A Kawagoe, Y. Tsuboi, (Chuo U.), S. Ueno, H. Tomida, S. Nakahira, M. Kimura, M. Ishikawa, Y. E. Nakagawa (JAXA), T. Mihara, M. Sugizaki, M. Morii, J. Sugimoto, T. Takagi, A. Yoshikawa, M. Matsuoka (RIKEN), N. Kawai, T. Yoshii, Y. Tachibana (Tokyo Tech), A. Yoshida, T. Sakamoto, Y. Kawakubo, H. Ohtsuki (AGU), H. Tsunemi, D. Uchida (Osaka U.), H. Negoro, M. Nakajima, K. Fukushima, T. Onodera, K. Suzuki (Nihon U.), Y. Ueda, M. Shidatsu, T. Kawamuro, T. Hori (Kyoto U.), M. Yamauchi, Y. Morooka (Miyazaki U.), K. Yamaoka (Nagoya U.) report on behalf of the MAXI team:
on 5 Apr 2014; 07:48 UT
Credential Certification: Motoko Suzuki (motoko@crab.riken.jp)
Subjects: X-ray, Star, Variables
On 2014-04-04 20:53 UT (=MJD 56751.87), the MAXI/GSC transient
alert system triggered on enhanced X-ray emission at
(R.A., Dec) = ( 278.233deg, 52.707deg ) = (07 34 37.584 +31 52 11.05) (J2000).
This location is 1.0 deg from BY Dra, which we suspect the source of this transient
on the basis of the positional agreement (though marginal).
BY Dra is an active binary star with star spots and flaring activities,
and a prototype of BY Dra-type stars (Rodono et al. 1986 A&A 165, 135).
The 2-20 keV flux averaged over the 44-second triangular transit was
about 40 mCrab, corresponding to a luminosity of 2 \times 10^31 ergs/s
for an assumed distance of 15.6 pc. The flux decayed to an upper limit
of ~20 mCrab at the next scan performed 92 minutes later.
This is the first flaring event that MAXI/GSC detected from this source.
