The Corona of the Hyperactive K Giant YY Men as Observed with Suzaku and the ATCA
Abstract
The single K giant YY Men (HD 32918) is one of the most active stars known within 300 pc of the Sun, having produced two of the most powerful radio flares and one of the most powerful and long-duration optical flares ever detected. Its corona is one of the hottest and brightest known, with a typical X-ray luminosity log Lx = 32.0-32.5 (log erg/s) which most other cool stars only reach during major flares. We have obtained a deep 100-ksec Suzaku observation of this hyperactive star in mid-June 2009 in order to get a high signal-to-noise X-ray spectrum of its corona, particularly in the 5-10 keV region in which the XIS excels. During this observation, YY Men showed no major X-ray variability, so we discuss the inferred properties of the time-integrated spectrum of YY Men at this epoch, e.g., the coronal abundances and differential emission measure, and the results of a search for the 6.4 keV fluorescent emission line and the constraints on the presence of ultrahigh thermal and/or non-thermal spectral components. We also discuss the simultaneous broad-band 3.6 and 6 cm microwave observations of YY Men that we have made with the ATCA, and compare the radio variability with the X-ray light curves.
- Publication:
-
AAS/High Energy Astrophysics Division #11
- Pub Date:
- March 2010
- Bibcode:
- 2010HEAD...11.1705D