Do Stellar X-ray Observations Provide Evidence For Solar-like Cycles?
Abstract
Utilizing 10 years of Yohkoh data, spanning nearly a complete solar cycle, we investigate the statistical variations of solar X-ray fluxes in the stellar context. The Yohkoh soft X-ray data can be described by the combination of a smoothly varying function representing the solar cycle plus a lognormal distribution representing the day-to-day variability in the lowest energy bands. Using data from the SXT filter which most closely resembles the ROSAT PSPC or Einstein IPC bandpasses, we examine the distribution of two ``snapshot'' samples of the Sun's X-ray emission taken at varying points in the cycle. Comparison with the ROSAT and Einstein ``snapshots'' of Hyades G stars strongly suggests that these more active ``suns'' have very long cycles, weak or no cycles, or cycles which are integral or sub-multiples of the solar cycle.
- Publication:
-
The Future of Cool-Star Astrophysics: 12th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun
- Pub Date:
- October 2003
- Bibcode:
- 2003csss...12..906S
- Keywords:
-
- Sun;
- Hyades;
- Stellar Activity