Simulations of the periodic flaring rate on YY Gem

Abstract

The binary YY Gem shows many interesting properties, one of which is the periodicity in its flaring rate. The period, which is about $48\pm 3$ min, was ever interpreted in terms of the oscillation of a filament. In this paper, we propose a new model to explain this phenomenon by means of 2.5-dimensional MHD numerical simulations. It is found that magnetic reconnection is induced as the coronal loops rooted on both stars inflate and approach each other, which is driven by the differential stellar rotation. The magnetic reconnection is modulated by fast-mode magnetoacoustic waves which are trapped between the surfaces of the two stars, so that the reconnection rate presents a periodic behaviour. With the typical parameters for the binary system, the observed period can be reproduced. We also derive an empirical formula to relate the period of the flaring rate to the coronal temperature and density, as well as the magnetic field.

arXiv comment9 pages, 9 figures, accepted by MNRAS

References in corpus (3)

• Absolute dimensions of the M-type eclipsing binary YY Geminorum (Castor C): a challenge to evolutionary models in the lower main-sequence
• Coronal density diagnostics with Helium-like triplets: CHANDRA--LETGS observations of Algol, Capella, Procyon, Eps Eri, Alpha Cen A&B, UX Ari, AD Leo, YY Gem, and HR1099
• Simultaneous X-ray spectroscopy of YY Gem with Chandra and XMM-Newton

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• Modelling Quasi-Periodic Pulsations in Solar and Stellar Flares
• Magnetic Field of the Eclipsing M Dwarf Binary YY Gem
• Possible evidence of induced repetitive magnetic reconnection in a superflare from a young solar-type star
• TYC 8380-1953-1: Discovery of an RS CVn binary through the XMM-Newton slew survey
• EvryFlare IV: Detection of periodicity in flare occurrence from cool stars with TESS