Planets and Stellar Activity: Hide and Seek in the CoRoT-7 system

By R. Haywood, A. Cameron, D. Queloz, S. Barros, M. Deleuil, R. Fares, M. Gillon, A. Hatzes, Antonino Francesco Lanza, C. Lovis and 6 more. 2013

328 citations recorded by the source corpus.

Abstract Since the discovery of the transiting Super-Earth CoRoT-7b, several investigations have been made of the number and precise masses of planets present in the system, but they all yield different results, owing to the star's high level of activity. Radial velocity (RV) variations induced by stellar activity therefore need to be modelled and removed to allow a reliable detection of all planets in the system. We re-observed CoRoT-7 in January 2012 with both HARPS and the CoRoT satellite, so that we now have the benefit of simultaneous RV and photometric data. We fitted the off-transit variations in the CoRoT lightcurve using a harmonic decomposition similar to that implemented in Queloz et al. (2009). This fit was then used to model the stellar RV contribution, according to the methods described by Aigrain et al. (2011). This model was incorporated into a Monte Carlo Markov Chain in order to make a precise determination of the orbits of CoRoT-7b and CoRoT-7c. We also assess the evidence for the presence of one or two additional planetary companions.

Subfields: Astronomy and Astrophysics

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Citations in the corpus

STELLAR AND PLANETARY PROPERTIES OF K2 CAMPAIGN 1 CANDIDATES AND VALIDATION OF 17 PLANETS, INCLUDING A PLANET RECEIVING EARTH-LIKE INSOLATION (2015, methodology): “A better strategy is to simultaneously fit both the signal and the systematics, as is common practice in cosmology and, increasingly, in radial velocity searches for planetary systems (e.g., Ferreira & Jaffe 2000; Boisse et al. 2011; Haywood et al. 2014; Grunblatt et al. 2015).”
MASS–RADIUS RELATION FOR ROCKY PLANETS BASED ON PREM (2015, neutral): “Table 1: CMF of Planets Planet M(M⊕) R(R⊕) CMF Earth1 1 1 0.325± 0.001 Venus1 0.815 0.9499 0.31± 0.01 K-10b 3.33± 0.49 (Dumusque et al. 2014) 1.47+0.03 −0.02 (Dumusque et al. 2014) 0.04± 0.2 K-36b 4.45+0.33 −0.27 (Carter et al. 2012) 1.486± 0.035 (Carter et al. 2012) 0.37± 0.14 K-78b 1.86+0.38 −0.25”
The HARPS search for southern extra-solar planets (2018, methodology): “In particular, in contrast to the case of Corot-7 (Haywood et al. 2014), the activity is weak and does not show significant correlation at the rotation period of the star (i.e., around 42 d).”
Limits on Planetary Companions from Doppler Surveys of Nearby Stars (2016, methodology): “Some groups are developing techniques to suppress stellar activity including modeling magnetic activity with time-series methods (Haywood et al. 2014; Grunblatt et al. 2015), identification and removal of photospheric signals (Hébrard et al. 2014), and Bayesian methods to identify noise by its…”
THE MASS OF Kepler-93b AND THE COMPOSITION OF TERRESTRIAL PLANETS (2014, methodology): “…planets with radii 50% larger than that of the Earth, all of which have extremely similar densities: Kepler-10b (ρ = 5.8±0.8 g cm−3; Dumusque et al. 2014), Kepler-36b (ρ = 7.46+0.74 −0.59 g cm −3; Carter et al. 2012), and CoRoT-7b (ρ = 6.56 ± 1.40 g cm−3; Barros et al. 2014; Haywood et al. 2014).”
DETERMINING THE MASS OF KEPLER-78b WITH NONPARAMETRIC GAUSSIAN PROCESS ESTIMATION (2015, methodology): “We expand upon the GP training technique used in Haywood et al. (2014) here.”