Coronal properties of planet-bearing stars

TL;DR

This study investigates whether star-planet interactions influence stellar X-ray activity by analyzing a comprehensive sample of nearby planet-hosting stars, finding no significant correlation between planetary parameters and X-ray activity.

Contribution

It provides the first large-scale statistical analysis of X-ray activity in planet-bearing stars, clarifying the role of star-planet interactions in stellar coronae.

Findings

No significant correlation between X-ray luminosity and planetary parameters.

Star-planet interactions are unlikely to have a major effect on stellar X-ray activity.

Coronal SPI effects may only be detectable in individual cases.

Abstract

Do extrasolar planets affect the activity of their host stars? Indications for chromospheric activity enhancement have been found for a handful of targets, but in the X-ray regime, conclusive observational evidence is still missing. We want to establish a sound observational basis to confirm or reject major effects of Star-Planet Interactions (SPI) in stellar X-ray emissions. We therefore conduct a statistical analysis of stellar X-ray activity of all known planet-bearing stars within 30pc distance for dependencies on planetary parameters such as mass and semimajor axis. We find that in our sample, there are no significant correlations of X-ray luminosity or the activity indicator L_X/L_bol with planetary parameters which cannot be explained by selection effects. Coronal SPI seems to be a phenomenon which might only manifest itself as a strong effect for a few individual targets, but not to have a major effect on planet-bearing stars in general.