Coronal Activity from the ASAS Eclipsing Binaries
Abstract
We combine the catalog of eclipsing binaries from the All Sky Automated Survey (ASAS) with the ROSAT All Sky Survey (RASS). The combination results in 836 eclipsing binaries that display coronal activity and is the largest sample of active binary stars assembled to date. By using the (V-I) colors of the ASAS eclipsing binary catalog, we are able to determine the distances and thus bolometric luminosities for the majority of eclipsing binaries that display significant stellar activity. A typical value for the ratio of soft X-ray to bolometric luminosity is LX/Lbol≈ a few ×10-4, similar to the ratio of soft X-ray to bolometric flux FX/Fbol in the most active regions of the Sun. Unlike rapidly rotating isolated late-type dwarfs - stars with significant outer convection zones - a tight correlation between Rossby number and activity of eclipsing binaries is absent. We find evidence for the saturation effect and marginal evidence for the so-called ``super-saturation'' phenomena. Our work shows that wide-field stellar variability searches can produce a high yield of binary stars with strong coronal activity.
The combined ASAS and RASS catalog, as well as the results of this work are available for download.- Publication:
-
Acta Astronomica
- Pub Date:
- December 2008
- DOI:
- 10.48550/arXiv.0812.3909
- arXiv:
- arXiv:0812.3909
- Bibcode:
- 2008AcA....58..405S
- Keywords:
-
- binaries: eclipsing;
- Stars: evolution;
- Stars: coronae;
- X-rays: binaries;
- Astrophysics
- E-Print:
- 15 pages, accepted for publication in Acta Astronomica