Abstract Details
| Name: Subhajeet Karmakar Affiliation: Aryabhatta Research Institute of observational Sciences (ARIES), Nainital Conference ID: ASI2018_562 Title : A Very Long and Hot X-ray Superflare on an RS CVn type eclipsing binary SZ PSc Authors and Co-Authors : Jeewan C. Pandey Aryabhatta Research Institute of observational Sciences (ARIES), Nainital Abstract Type : Contributed Talk Abstract Category : Stars,ISM and the Galaxy Abstract : We present an analysis of a very large flare from the 3.966-day period RS CVn type eclipsing binary system SZ Psc which triggered the Swift Burst Alert Telescope (BAT) hard X-ray detector at 09:08:42 UT on 15 January 2015. The flare lasts more than 100 ks is the longest duration X-ray flare ever observed as the best of our knowledge. The exponential rise and decay time of the flares were derived to be 2 and 5 hr, respectively. The peak X-ray luminosity in 0.3-10 keV energy band reached to a value of 4.8 x 10^{33} erg s^{−1}, which is 89 times more than that of the observed minimum value.Spectral analysis indicates a presence of one temperature corona, which represents the flare temperature. The temperature is one of the highest observed spectroscopically with a peak at 258 MK, which is ∼ 10 times more than the observed minimum value. The peak stellar abundances were derived to be 0.7 times more than solar abundances, which is also 10 times more than that of the minimum abundance observed on SZ Psc. The Emission Measure followed the flare light curve and peaked at a value of 2.53 × 10^{54} cm^{−3}, which is ∼17 times more than the quiescent value. The length of the flaring plasma was derived to be 7.3 x 10^{11} cm, whereas the loop apex pressure and the peak density were derived to be 9.1 x 10^{4} dyne/cm^{2} and 5.8 x 10^{11} cm^{-3}, respectively. The total magnetic field estimated to produce the flare is 1.5 kG. Preliminary analysis suggests that the large magnetic field at the coronal height is due to the presence of extended convection zone of the sub-giant and the high orbital velocity. |