Planets in Binary Systems Alteration of Chemical Abundances Search and Characterization of Transiting Planets Radial Velocity Variation in Red Giants

Planets in Binary Systems

Figure 1: courtesy of G. Galletta.

The search for planets in multiple systems allows to improve our knowledge on planet formation and evolution. On one hand, the frequency of planets in binary systems has a strong effect on the global frequency of planets, as more than half of solar type stars are in binary or multiple systems. On the other hand, the properties of planets in binaries, and any difference with those of the planets orbiting single stars would shed light on the effects caused by the presence of the companions.

A radial velocity survey aimed to look for planets in binaries is ongoing using SARG at TNG. The selected systems are pairs with similar components, to make the search for signatures of planetary accretion easier, with typical separation of about 100-300 astronomical units.

Figure 2: Radial velocity curve of 51 Peg obtained with SARG

The bulk of the survey to search for planets in binary systems performed using SARG at TNG was just completed, with further observations already scheduled aimed at the confirmation of a few very promising planet candidates. The lack of planets with period shorter than 7 years and velocity amplitude larger than about 30 m/s suggests a lower frequency of planets with respect to comparison samples formed mostly of single stars.
Indications for a significant role of binarity on the planet formation processes were also derived from our study of the statistical properties of planets in binaries: planets orbiting components of moderately close binaries show a different mass function with respect to those orbiting components of wide binaries and single stars.

cumul_mass SARG with the same set-up used for planet search was also successfully used for asteroseismology campaigns. Averaging the data taken in individual nights results in typical dispersion of nightly averages of about 20 cm/s. This opens the perspective of using SARG to search for low mass planets in close orbits.

People: S. Desidera, R. Gratton, R. Claudi, S. Lucatello, S. Benatti, M. Bonavita, E. Carolo

Collaboration: M. Endl (Mc Donald Observatory), G. Bonanno, R. Cosentino, S. Scuderi (INAF OA Catania), A.F. Martinez Fiorenzano (TNG), M. Barbieri (Laboratoire d'Astrophysique de Marseille), F. Marzari (Padova Univ.)

Recent Publications: Desidera et al. (2007) astro-ph 0705.3141; Desidera & Barbieri (2007) A&A 462,345