X-ray Activity and Close-in Giant Planets
Abstract
We have carried out a survey of X-ray emission from stars with close-in giant planets. Of the greater than 150 stars that have been identified as possessing planets, a third have been detected in observations carried out with ROSAT and XMM. We carry out detailed statistical analyses, comparing subsamples of stars that have close-in planets with stars that have more distant planets. We establish that X-ray activity is higher for stars with close-in giant planets. This result is highly robust and persists for various sample subsets. We attempt to explain this difference as possibly due to sample biases and find that a significant residual difference still remains. We interpret this observational result as being due to the effect of the physical presence of giant planets in close proximity to the stars. Whether this is a causal effect or an accidental correlation cannot be decided with the data at hand. We posit that the interactions between the planetary and stellar magnetospheres could be the physical cause of the enhancement.
This research was supported by NASA contract NAS8-39073 (CXC), and NASA grants NNG05GJ63G (XMM/GO) and NAG-10360 (Origins).- Publication:
-
AAS/High Energy Astrophysics Division #10
- Pub Date:
- March 2008
- Bibcode:
- 2008HEAD...10.1704K