Planets in Binary Systems
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| Figure 1: courtesy of G. Galletta.
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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.
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| Figure 2: Radial velocity curve of 51 Peg obtained with SARG
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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.
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
