Extrasolar Giant Planets and X-ray Activity

TL;DR

This study finds that stars with close-in giant planets exhibit significantly higher X-ray activity than those with distant planets, suggesting planetary influence on stellar magnetic activity.

Contribution

It provides the first statistical evidence linking close-in giant planets to increased stellar X-ray activity, supporting planetary influence on stellar magnetic phenomena.

Findings

Stars with close-in giant planets are ~4 times more X-ray active.

The increased activity persists after accounting for observational biases.

The results support the hypothesis of planetary influence on stellar magnetic 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 a 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 ~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 influences the stellar magnetic activity.