Extrasolar Giant Planets and X-Ray Activity
Abstract
We have carried out a survey of X-ray emission from stars with giant planets, combining both archival and targeted surveys. Over 230 stars have been currently identified as possessing planets, and roughly one-third of these have been detected in X-rays. We carry out detailed statistical analysis on a volume-limited sample of main-sequence star systems with detected planets, comparing subsamples of stars that have close-in planets with stars that have more distant planets. This analysis reveals strong evidence that stars with close-in giant planets are on average more X-ray active by a factor of ≈4 than those with planets that are more distant. This result persists for various sample selections. We find that even after accounting for observational sample bias, a significant residual difference still remains. This observational result is consistent with the hypothesis that giant planets in close proximity to the primary stars influence the stellar magnetic activity.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- November 2008
- DOI:
- 10.1086/591922
- arXiv:
- arXiv:0807.1308
- Bibcode:
- 2008ApJ...687.1339K
- Keywords:
-
- methods: statistical;
- planetary systems;
- stars: activity;
- stars: magnetic fields;
- surveys;
- X-rays: general;
- Astrophysics
- E-Print:
- accepted for publication in ApJ