Extrasolar planets in double and multiple stellar systems

Abstract

About 60% of G and K dwarfs belong to double or multiple stellar systems, making these a common environment in which planets may form. Despite this, close binaries have often been rejected from radial-velocity searches for extrasolar planets because they present observational difficulties. Planet formation and survival in binaries is thus a poorly known issue, though interesting in several respects. In particular, stellar duplicity could be used to test planet formation models and possibly identify the main formation mechanism for giant planets. For a few years we have been conducting two observational programmes dedicated to the study of extrasolar planets in binaries. The first one is a radial-velocity search for short-period giant planets in spectroscopic binaries, while the second one is a systematic adaptive optics search for stellar companions to nearby stars with and without planetary companions. In this contribution we first review some observational and theoretical aspects related to extrasolar planets in binaries. We then present some preliminary results from our two observational programmes. © 2008 Springer-Verlag Berlin Heidelberg.