Eccentricities of Planets in Binary Systems

Details Eccentricities of Planets in Binary Systems Eccentricities of Planets in Binary Systems

2005-10-10

arxiv.org/abs/astro-ph/0510296v1

Astronomy and Astrophysics

Astrophysics

8 pages, to appear in "Close Binaries in the 21st Century: New Opportunities and Challenges", ed. A. Gimenez et al. (Springer)

Scientific paper

10.1007/s10509-006-9120-1

The most puzzling property of the extrasolar planets discovered by recent radial velocity surveys is their high orbital eccentricities, which are very difficult to explain within our current theoretical paradigm for planet formation. Current data reveal that at least 25% of these planets, including some with particularly high eccentricities, are orbiting a component of a binary star system. The presence of a distant companion can cause significant secular perturbations in the orbit of a planet. At high relative inclinations, large-amplitude, periodic eccentricity perturbations can occur. These are known as "Kozai cycles" and their amplitude is purely dependent on the relative orbital inclination. Assuming that every planet host star also has a (possibly unseen, e.g., substellar) distant companion, with reasonable distributions of orbital parameters and masses, we determine the resulting eccentricity distribution of planets and compare it to observations? We find that perturbations from a binary companion always appear to produce an excess of planets with both very high (e>0.6) and very low (e<0.1) eccentricities. The paucity of near-circular orbits in the observed sample implies that at least one additional mechanism must be increasing eccentricities. On the other hand, the overproduction of very high eccentricities observed in our models could be combined with plausible circularization mechanisms (e.g., friction from residual gas) to create more planets with intermediate eccentricities (e=0.1-0.6).

Affiliated with

Also associated with

No associations

Rating

Eccentricities of Planets in Binary Systems does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Eccentricities of Planets in Binary Systems, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Eccentricities of Planets in Binary Systems will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-48223