Abstract

The CoRoT space mission observed 163 665 stars over 26 stellar fields in the faint star channel. The exoplanet teams detected a total of 4123 transit-like features in the 177 454 light curves. We present the complete re-analysis of all these detections carried out with the same softwares so that to ensure their homogeneous analysis. Although the vetting process involves some human evaluation, it also involves a simple binary flag system over basic tests: detection significance, presence of a secondary, difference between odd and even depths, colour dependence, V-shape transit, and duration of the transit. We also gathered the information from the large accompanying ground-based programme carried out on the planet candidates and checked how useful the flag system could have been at the vetting stage of the candidates. From the initial list of transit-like features, we identified and separated 824 false alarms of various kind, 2269 eclipsing binaries among which 616 are contact binaries and 1653 are detached ones, 37 planets and brown dwarfs, and 557 planet candidates. We provide the catalogue of all these transit-like features, including false alarms. For the planet candidates, the catalogue gives not only their transit parameters but also the products of their light curve modelling: reduced radius, reduced semi-major axis, and impact parameter, together with a summary of the outcome of follow-up observations when carried out and their current status. For the detached eclipsing binaries, the catalogue provides, in addition to their transit parameters, a simple visual classification. Among the planet candidates whose nature remains unresolved, we estimate that eight (within an error of three) planets are still to be identified. After correcting for geometric and sensitivity biases, we derived planet and brown dwarf occurrences and confirm disagreements with Kepler estimates, as previously reported by other authors from the analysis of the first runs: small-size planets with orbital period less than ten days are underabundant by a factor of three in the CoRoT fields whereas giant planets are overabundant by a factor of two. These preliminary results would however deserve further investigations using the recently released CoRoT light curves that are corrected of the various instrumental effects and a homogeneous analysis of the stellar populations observed by the two missions.

Highlights

  • The CoRoT space mission (Baglin et al 2006) operated fromJanuary 2007 to October 2012, with the two core science goals of discovering transiting exoplanets and probing the structure of stars through asteroseismology

  • Having performed the visual vetting and the follow-up, we can use the benefit of hindsight to investigate, after the fact, to what extent the flag system could have been used in this manner

  • We provide the full catalogue of all the transit-like events identified in the CoRoT light curves during the mission lifetime by the CoRoT collaboration

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Summary

Introduction

January 2007 to October 2012, with the two core science goals of discovering transiting exoplanets and probing the structure of stars through asteroseismology During this period, the instrument photometrically monitored 163 665 targets distributed over stellar fields in two opposite regions in the galactic plane. (Carone et al 2012) SRc01 (Erikson et al 2012), and LRa03 and SRa03 (Cavarroc et al 2012), with a comparison between predicted and observed rates of false positives from the first three long runs (IRa01 to LRa01) given by Almenara et al (2009) This procedure was discontinued in favour of collating all the candidates from all the stellar fields, and their status at the end of the follow-up programme, in a single location.

The CoRoT exoplanet mission profile
Photometry in the exoplanet chanel
Observation programme
Transit detection
Transit candidate detection and vetting
Initial transit candidate vetting
Transit candidate modelling
Eclipsing binaries
Flag system
Statistics of the candidates
Follow-up observations of the candidates
Outcome of the follow-up observations
Evaluation of the candidate screening process
Candidates versus EBs
Follow-up results versus flagging
Unresolved candidates
CoRoT planet occurrences
Small size planet occurrences
Giant planet occurrences
Brown dwarf occurrences
Summary
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