ROSAT Observations of the Flare Star CC Eri

Abstract

The flare/spotted spectroscopic binary star CC Eri was observed with the Position Sensitive Proportional Counter (PSPC) on the X-ray satellite ROSAT on 1990 July 9-11 and 1992 January 26-27. During the observations, the source was variable on time scales from a few minutes to several hours, with the X-ray (0.2-2 keV) luminosity in the range $\sim 2.5-6.8\times 10^{29}erg{s}^{-1}$. An X-ray flare-like event, which has a one hour characteristic rise time and a two hour decay time, was observed from CC Eri on 1990 July 10 16:14-21:34 (UT). The X-ray spectrum of the source can be described by current thermal plasma codes with two temperature components or with a continuous temperature distribution. The spectral results show that plasma at $Te\sim 10^7$ K exists in the corona of CC Eri. The variations in the observed source flux and spectra can be reproduced by a flare, adopting a magnetic reconnection model. Comparisons with an unheated model, late in the flare, suggest that the area and volume of the flare are substantially larger than in a solar two ribbon flare, while the electron pressure is similar. The emission measure and temperature of the non-flaring emission, interpreted as the average corona, lead to an electron pressure similar to that in a well-developed solar active region. Rotational modulation of a spot related active region requires an unphysically large X-ray flux in a concentrated area.

14 pages, compressed and uuencoded postscript file, to be published in MNRAS

Cited by in corpus (7)

• The Structure of Stellar Coronae in Active Binary Systems
• Large X-ray Flares on Stars Detected with MAXI/GSC: A Universal Correlation between the Duration of a Flare and its X-ray Luminosity
• The corona and upper transition region of epsilon Eridani
• X-ray flares on the UV Ceti-type star CC Eridani: a "peculiar" time-evolution of spectral parameters
• X-Ray Superflares on CC Eri
• On the filling factor of emitting material in the upper atmosphere of Epsilon Eri (K2 V)
• A burst from the direction of UZ Fornacis with XMM-Newton