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Flare and quiescent X-ray emission from Sigma Geminorum

R. Nordon·E. Behar·M. Guedel
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Abstract

The X-ray active RS CVn binary system Sigma Geminorum was observed during a long-duration flare with XMM-Newton. We compare line emission during the flare with line emission measured from a previous Chandra observation during quiescence, in a model independent way. We find that in addition to an overall 25% flux increase, which can be ascribed to variations in the system's quiescence activity over the 15 months that passed between the observations, there is a hot plasma component of kT_e > 1 keV that arises with the flare. The hot component is manifested primarily by high charge states of Fe and by a vast continuum, but with no temperature or abundance effect on the cooler plasma, except perhaps for Mg that is anomalously enhanced.

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R. Nordon, E. Behar, M. Guedel. 2004-09-20. Flare and quiescent X-ray emission from Sigma Geminorum. https://arxiv.org/abs/astro-ph/0409472

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