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On Temperature and Abundance Effects During an X-Ray Flare on Sigma Geminorum

R. Nordon·E. Behar·M. Guedel
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Abstract

We compare quiescent and flare X-ray spectra of the RS CVn binary Sigma Gem obtained with the Chandra and XMM-Newton grating spectrometers. 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 > 3 keV that arises with the flare. The hot component is manifested primarily by emission from high charge states of Fe and by a vast continuum. The cooler (kT_e < 2 keV) plasma remains undisturbed during the flare. We find no significant variations in the relative abundances during the flare except for a slight decrease (<30%) of O and Ne.

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R. Nordon, E. Behar, M. Guedel. 2005-10-02. On Temperature and Abundance Effects During an X-Ray Flare on Sigma Geminorum. https://doi.org/10.1051/0004-6361%3A20054018

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