Volume 588, April 2016
|Number of page(s)||7|
|Section||Planets and planetary systems|
|Published online||14 March 2016|
Uncovering the planets and stellar activity of CoRoT-7 using only radial velocities ⋆
Instituto de Astrofísica e Ciências do Espaço, Universidade do
CAUP, Rua das Estrelas,
2 Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Rua Campo Alegre, 4169-007 Porto, Portugal
3 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
4 Department of Statistics, The University of Auckland, Private Bag 92019, 1142 Auckland, New Zealand
5 Institut für Astrophysik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
Received: 4 December 2015
Accepted: 27 January 2016
Stellar activity can induce signals in the radial velocities of stars, complicating the detection of orbiting low-mass planets. We present a method to determine the number of planetary signals present in radial-velocity datasets of active stars, using only radial-velocity observations. Instead of considering separate fits with different number of planets, we use a birth-death Markov chain Monte Carlo algorithm to infer the posterior distribution for the number of planets in a single run. In a natural way, the marginal distributions for the orbital parameters of all planets are also inferred. This method is applied to HARPS data of CoRoT-7. We confidently recover the orbits of both CoRoT-7b and CoRoT-7c although the data show evidence for the presence of additional signals.
Key words: methods: data analysis / planetary systems / stars: individual: CoRoT-7 / techniques: radial velocities
All data and software presented in this article are available online at https://github.com/j-faria/exoBD-CoRoT7
© ESO, 2016
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