The Astrophysical Journal, 580:L73L76, 2002 November 20
2002. The American Astronomical Society. All rights reserved. Printed in U.S.A.
X-RAY EVIDENCE FOR FLARE DENSITY VARIATIONS AND CONTINUAL CHROMOSPHERIC
EVAPORATION IN PROXIMA CENTAURI
Stephen L. Skinner,3
and Matthias I. Horvath4
Received 2002 August 23; accepted 2002 October 4; published 2002 October 16
Using the XMM-Newton X-ray observatory to monitor the nearest star to the Sun, Proxima Centauri, we recorded
the weakest X-ray flares on a magnetically active star ever observed. Correlated X-ray and optical variability provide
strong support for coronal energy and mass supply by a nearly continuous sequence of rapid explosive energy
releases. Variable emission-line fluxes were observed in the He-like triplets of O vii and Ne ix during a giant flare.
They give direct X-ray evidence for density variations, implying densities between and cm 310 11
2 # 10 4 # 10
and providing estimates of the mass and the volume of the line-emitting plasma. We discuss the data in the context
of the chromospheric evaporation scenario.
Subject headings: stars: activity -- stars: coronae -- stars: flare -- stars: individual (Proxima Centauri) --