Swift and XMM-Newton observations of an RS CVn-type eclipsing binary SZ Psc: superflare and coronal properties
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 $\rm {erg}~\rm {s}^{-1}$. 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 $\rm {Z}_{\odot }$, 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.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- January 2023
- DOI:
- 10.1093/mnras/stac2970
- arXiv:
- arXiv:2210.07170
- Bibcode:
- 2023MNRAS.518..900K
- Keywords:
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- stars: activity;
- stars: coronae;
- stars: flare;
- stars: individual (SZ Psc);
- stars: magnetic field;
- X-rays: stars;
- Astrophysics - Solar and Stellar Astrophysics;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 23 pages, 12 figures, 5 tables, accepted for publication in MNRAS