Coronal properties of planet-bearing stars

K. Poppenhaeger, J. Robrade, J. H. M. M. Schmitt

Published 2010-03-30Version 1

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.