Abstract:
We present an in-depth study of a large and long duration (>1.3 d) X-ray flare observed on an RS CVn-type eclipsing binary
system SZ Psc using observations from Swift observatory. In the 0.35–10 keV energy band, the peak luminosity is estimated to
be 4.2 × 1033 erg s−1. The quiescent corona of SZ Psc was observed ∼5.67 d after the flare using Swift observatory, and also
∼1.4 yr after the flare using the XMM–Newton satellite. The quiescent corona is found to consist of three temperature plasma: 4,
13, and 48 MK. High-resolution X-ray spectral analysis of the quiescent corona of SZ Psc suggests that the high first ionization
potential (FIP) elements are more abundant than the low-FIP elements. The time-resolved X-ray spectroscopy of the flare shows
a significant variation in the flare temperature, emission measure, and abundance. The peak values of temperature, emission
measure, and abundances during the flare are estimated to be 199 ± 11 MK, 2.13 ± 0.05 × 1056 cm−3, 0.66 ± 0.09 Z ,
respectively. Using the hydrodynamic loop modelling, we derive the loop length of the flare as 6.3 ± 0.5 × 1011 cm, whereas
the loop pressure and density at the flare peak are derived to be 3.5 ± 0.7 × 103 dyn cm−2 and 8 ± 2 × 1010 cm−3, respectively.
The total magnetic field to produce the flare is estimated to be 490 ± 60 G. The large magnetic field at the coronal height is
supposed to be due to the presence of an extended convection zone of the subgiant and the high orbital velocity.
