3 Ms in the Life of β Ceti: Sustained Flare Activity on a Clump Giant Detected by the Extreme Ultraviolet Explorer
Abstract
A 34 day Extreme Ultraviolet Explorer (EUVE) pointing on the ``clump'' giant β Ceti (HD 4128; K0 III) recorded a series of striking coronal flare events, reminiscent of a singular outburst seen previously from μ Velorum (HD 93497; G6 III + dF). The recent flaring episode contrasts with a more placid behavior in a 6 day EUVE observation of β Cet 6 years earlier. The average 70-180 Å Deep Survey count rate in the new observation is twice as high, and the 75-150 Å spectrum displays a distinct hardening. The discovery of sustained flare activity on β Cet raises the possibility that such episodes are more common than suspected among the core helium-burning giants and sharpens the puzzle of the survival of magnetic activity beyond helium flash.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- November 2001
- DOI:
- 10.1086/337971
- Bibcode:
- 2001ApJ...562L..83A
- Keywords:
-
- Stars: Activity;
- Stars: Coronae;
- Stars: Flare;
- Stars: Individual: Henry Draper Number: HD 4128;
- Stars: Individual: Henry Draper Number: HD 93497;
- Stars: Late-Type;
- Ultraviolet: Stars