Transiting exoplanets from the CoRoT space mission

Author(s)

H. Parviainen, D. Gandolfi, M. Deleuil, C. Moutou, H. J. Deeg, S. Ferraz-Mello, B. Samuel, Sz Csizmadia, T. Pasternacki, G. Wuchterl, M. Havel, M. Fridlund, R. Angus, B. Tingley, S. Grziwa, J. Korth, S. Aigrain, J. M. Almenara, R. Alonso, A. Baglin, S. C.C. Barros, P. Bordé, F. Bouchy, J. Cabrera, R. F. Díaz, R. Dvorak, A. Erikson, T. Guillot, A. Hatzes, G. Hébrard, T. Mazeh, G. Montagnier, A. Ofir, M. Ollivier, M. Pätzold, H. Rauer, D. Rouan, A. Santerne, J. Schneider

Abstract

Aims. We report the discovery of a massive and dense transiting planet CoRoT-27b on a 3.58-day orbit around a 4.2 Gyr-old G2 star. The planet candidate was identified from the CoRoT photometry, and was confirmed as a planet with ground-based spectroscopy. Methods. The confirmation of the planet candidate is based on radial velocity observations combined with imaging to rule out blends. The characterisation of the planet and its host star was carried out using a Bayesian approach where all the data (CoRoT photometry, radial velocities, and spectroscopic characterisation of the star) are used jointly. The Bayesian analysis included a study whether the assumption of white normally distributed noise holds for the CoRoT photometry and whether the use of a non-normal noise distribution offers advantages in parameter estimation and model selection. Results. CoRoT-27b has a mass of 10.39 ± 0.55M

_Jup, a radius of 1.01 ± 0.04R

_Jup, a mean density of $12.6

_-1.67

^+1.92$g cm

^-3, and an effective temperature of 1500 ± 130 K. The planet orbits around its host star, a 4.2 Gyr-old G2-star with a mass M

_† = 1.06M

_™ and a radius R

_† = 1.05R

_™, on a 0.048 ± 0.007 AU orbit of 3.58 days. The radial velocity observations allow us to exclude highly eccentric orbits, namely, e < 0.065 with 99% confidence. Given its high mass and density, theoretical modelling of CoRoT-27b is demanding. We identify two solutions with heavy element mass fractions of 0.11 ± 0.08MâŠ• and 0.07 ± 0.06M

_âŠ•, but even solutions void of heavy elements cannot be excluded. We carry out a secondary eclipse search from the CoRoT photometry using a method based on Bayesian model selection, but conclude that the noise level is too high to detect eclipses shallower than 9% of the transit depth. Using a non-normal noise model was shown not to affect the parameter estimation results, but led to significant improvement in the sensitivity of the model selection process.

Organisation(s)

Department of Astrophysics

External organisation(s)

Institute of Astrophysics of the Canary Islands, University of La Laguna, INAF-Osservatorio Astrofisico di Catania, Aix-Marseille Université, Instituto Oceanográfico, Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR), Thüringer Landessternwarte Tautenburg, National Aeronautics & Space Administration (NASA), Science and Operations Department - Science Division (SCI-SC), Aarhus University, Universität zu Köln, Université Paris XI - Paris-Sud, Observatoire de Haute-Provence, Tel Aviv University, Georg-August-Universität Göttingen, Universidade do Porto, Paris Observatory, University of Oxford, Université Paris VII - Paris-Diderot, Institut d'astrophysique de Paris (IAP), UMR7095 - CNRS, Université Côte d'Azur

Journal

Astronomy & Astrophysics

Volume

562

No. of pages

ISSN

0004-6361

DOI

https://doi.org/10.1051/0004-6361/201323049

Publication date

02-2014

Peer reviewed

Yes

Austrian Fields of Science 2012

103003 Astronomy, 103004 Astrophysics

Keywords

ASJC Scopus subject areas

Astronomy and Astrophysics, Space and Planetary Science

Portal url

https://ucrisportal.univie.ac.at/en/publications/59203a86-01e5-45fc-af76-cea4d823ba26

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