Coronal properties of planet-bearing stars

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

Hamburger Sternwarte, University Hamburg, Gojenbergsweg 112, 21029 Hamburg, Germany e-mail: katja.poppenhaeger@hs.uni-hamburg.de

Received: 11 February 2010
Accepted: 20 March 2010

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 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.