2004/09/20 by R. Nordon, E. Behar, Ehud Behar +5
Physics and Astronomy · #Astro and Planetary Science #Astrophysical Phenomena and Observations #Astrophysics (astro-ph) #FOS: Physical sciences #Gamma-ray bursts and supernovae #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0409472
4 pages, 5 figures. To appear in the proceedings of Cool Stars 13 conference
arxiv created 2004/09/20 · openalex publication_date 2004/09/20 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
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 kTe > 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.