Coronal properties of planet-bearing stars

Abstract

Context. 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. Aims.We want to establish a sound observational basis to confirm or reject major effects of Star-Planet Interactions (SPI) in stellar X-ray emissions. Methods.We therefore conduct a statistical analysis of stellar X-ray activity of all known planet-bearing stars within 30 pc distance for dependencies on planetary parameters such as mass and semimajor axis. Results. In our sample, there are no significant correlations of X-ray luminosity or the activity indicator LX/Lbol with planetary parameters which cannot be explained by selection effects. Conclusions.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. © 2010 ESO.