Chromospheric activity of stars with planets

Departamento de Física, Universidade Federal do Rio Grande do Norte, Natal, Brazil
e-mail: brunocanto@dfte.ufrn.br

Received: 30 June 2010
Accepted: 25 March 2011

Abstract

Context. Signatures of chromospheric activity enhancement have been found for a dozen stars, pointing to a possible star-planet interaction. Nevertheless in the coronal activity regime, there is no conclusive observational evidence of such an interaction. Does star-planet interaction manifest itself only for a few particular cases, without having a major effect on stars with planets in general?

Aims. We aim to add additional observational constraints to support or reject the major effects of star-planet interactions in stellar activity, based on Ca II chromospheric emission flux.

Methods. We performed a statistical analysis of Ca II emission flux of stars with planets, as well as a comparison between Ca II and X-ray emission fluxes, searching for dependencies on planetary parameters.

Results. In the present sample of stars with planets, there are no significant correlations between chromospheric activity indicator log(R’_HK) and planetary parameters. Furthermore, the distribution of the chromospheric activity indicator for stars without planets is indistinguishable from the one with planets.