MAXI/GSC detection of a possible X-ray flare from an RS CVn star HR5110
ATel #9144; R. Sasaki, Y. Tsuboi, Y. Nakamura (Chuo U.), M. Serino (RIKEN), S. Ueno, H. Tomida, S. Nakahira, M. Ishikawa, Y. E. Nakagawa, Y. Sugawara (JAXA), T. Mihara, M. Sugizaki, W. Iwakiri, M. Shidatsu, J. Sugimoto, T. Takagi, M. Matsuoka (RIKEN), N. Kawai, N. Isobe, S. Sugita, T. Yoshii, Y. Tachibana, Y. Ono, T. Fujiwara (Tokyo Tech), A. Yoshida, T. Sakamoto, Y. Kawakubo, Y. Kitaoka (AGU), H. Tsunemi, R. Shomura (Osaka U.), H. Negoro, M. Nakajima, K. Tanaka, T. Masumitsu, T. Kawase (Nihon U.), Y. Ueda, T. Kawamuro, T. Hori, A. Tanimoto (Kyoto U.), M. Yamauchi, K. Furuya (Miyazaki U.), K. Yamaoka (Nagoya U.)
on 13 Jun 2016; 12:55 UT
Credential Certification: Yohko Tsuboi (tsuboi@phys.chuo-u.ac.jp)
Subjects: X-ray, Binary, Star, Transient, Variables
MAXI/GSC observed a possible X-ray flare from an RS CVn star HR5110.
The MAXI/GSC nova alert system triggered on the flare-like event from the position consistent with the RS CVn system HR5110 during a scan transit at 09:19:00 UT on June 12th 2016. Any source was not detected significantly (< 20 mCrab at 4-10 keV) with MAXI/GSC during the next transit at 10:51:32 UT on the same day. The position of the X-ray enhancement is (203.261 deg, 37.069 deg) = (13 33 02, +37 04 08) (J2000) with a statistical 90% C.L. elliptical error region with long and short radii of 0.52 deg and 0.43 deg respectively. The roll angle of the long axis from the north direction is 35.0 deg. There is an additional systematic uncertainty of 0.1 deg (90% containment radius). The position was determined with the data obtained at one scan transits from 09:15:36 UT on June 12th to 09:22:09 UT on the same day. This position is consistent with that of an RS CVn star, HR5110, which is listed in the ROSAT Bright Source Catalog. No other source listed in the catalog is in the error region.
The 4-10 keV flux averaged over the one scan transits was about 95+-24 mCrab. These are corresponding to a luminosity of 6× 10 32 ergs/s for an assumed distance of 53 pc. This is the first detection of this source with MAXI/GSC.