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Comparing HARPS and Kepler surveys: on the alignement of multiple-planet systems

Pedro Figueira

The recent results of the HARPS and Kepler surveys provided us with a bounty of extrasolar systems. While the two teams analyzed extensively each of their data-sets, little work has been done comparing the two. We study a subset of the planetary population whose characterization is simultaneously within reach of both instruments. In this talk I compare the statistical properties of planets in systems with m sin i >5-10 M and R >2 R, as inferred from HARPS and Kepler surveys, respectively. If we assume that the underlying population has the same characteristics, the different detection sensitivity to the orbital inclination relative to the line of sight allows us to probe the planets' mutual inclination.
I will show that the distribution of planets relative to a reference plane are better described by a Rayleigh distribution with mode of 1° or smaller, and are thus strongly aligned.These results have important consequences for our understanding of the role of several proposed formation and evolution mechanisms. They confirm that planets are likely to have been formed in a disk and show that most planetary systems evolve quietly without strong angular momentum exchanges such as those produced by Kozai mechanism or planet scattering.

Related publications:
Comparing HARPS and Kepler surveys: on the alignement of multiple-planet systems

2012 February 28, 13:30

Centro de Astrofísica da Universidade do Porto (Auditorium)
Rua das Estrelas, 4150-762 Porto

Faculdade de Ciências da Universidade de Lisboa Universidade do Porto Faculdade de Ciências e Tecnologia da Universidade de Coimbra
Fundação para a Ciência e a Tecnologia COMPETE 2020 PORTUGAL 2020 União Europeia