Gandolfi, D.; Parviainen, H.; Deleuil, M.; Moutou, C.; Deeg, H. J.; Ferraz-Mello, S.; Samuel, B.; Csizmadia, Sz.; Pasternacki, T.; Wuchterl, G.; Havel, M.; Fridlund, M.; Angus, R.; Tingley, B.; Grziwa, S.; Korth, J.; Aigrain, S.; Almenara, J. M.; Alonso, R.; Baglin, A.; Barros, S. C. C.; Bordé, P.; Bouchy, F.; Cabrera, J.; Díaz, R. F.; Dvorak, R.; Erikson, A.; Guillot, T.; Hatzes, A.; Hébrard, G.; Mazeh, T.; Montagnier, G.; Ofir, A.; Ollivier, M.; Pätzold, M.; Rauer, H.; Rouan, D.; Santerne, A.; Schneider, J.
Referencia bibliográfica
Astronomy and Astrophysics, Volume 562, id.A140, 12 pp.
Fecha de publicación:
2
2014
Número de autores del IAC
3
Número de citas referidas
21
Descripción
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 ± 0.55MJup, a radius of 1.01 ±
0.04RJup, a mean density of
12.6-1.67+1.92g 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
± 0.08M⊕ and 0.07 ± 0.06M⊕, 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.
The CoRoT space mission, launched on December 27, 2006, has been
developed and is operated by the CNES, with the contribution of Austria,
Belgium, Brazil, ESA (RSSD and Science Programme), Germany, and Spain.
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