Uncovering the planets and stellar activity of CoRoT-7 using only radial velocities

TL;DR

This paper introduces a novel Bayesian method using birth-death MCMC to identify the number of planets in radial velocity data of active stars, effectively distinguishing planetary signals from stellar activity.

Contribution

The paper presents a new approach that infers the number of planets and their parameters simultaneously from radial velocity data using a birth-death MCMC algorithm.

Findings

Successfully recovered CoRoT-7b and CoRoT-7c signals

Detected additional potential signals in the data

Demonstrated effectiveness on HARPS observations

Abstract

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 both CoRoT-7b and CoRoT-7c although the data show evidence for additional signals.