The multiplicity of exoplanet host stars

M. Mugrauer*, R. Neuhaeuser, E. Guenther, T. Mazeh

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


We present the latest results from our systematic imaging search for visual companions of exoplanet host stars. Several new wide companions were detected, extending the sample size of multiple stellar systems known to harbor exoplanets by about 25%. These new results can be used to study the influence of the stellar multiplicity on the exoplanets, e.g. differences in the planet properties compared to planets orbiting a single star. Our IR imaging survey is carried out at UKIRT and Calar Alto Observatory for the northern targets and at La Silla Observatory for southern targets, and can find all directly detectable stellar and substellar companions (m>40MJup) with projected separations from 50 to 1000 AU (see Mugrauer et al. 2005, A&A). Furthermore we present first results of our new high contrast AO imaging program. We use NACO/VLT with its new simultaneous differential imager (SDI) to search for close companions of all exoplanet host stars which harbor several substellar companions, i.e. several planets or planets and a brown dwarf. We discuss in particular the binary system G186AB, one of the closest binaries with an exoplanet known today. The companion G186B is separated from the exoplanet host star by only 20AU and with precise NACO/SDI astrometry we could detected its orbital motion around the primary star. In addition with NACO spectroscopy we found evidence that G186B is a white dwarf, the first known close white dwarf companion to an exoplanet host star (see Mugrauer & Neuhäuser, 2005, MNRAS).

Original languageEnglish
Pages (from-to)629-630
Number of pages2
JournalAstronomische Nachrichten
Issue number7
StatePublished - 2005

Cite this