CoRoT Results

CoRoT-21, a F8IV star of magnitude V=16 mag, was observed by the space telescope CoRoT during the Long Run 01 (LRa01) in the first winter field (constellation Monoceros) from October 2007 to March 2008. Transits were discovered during the light curve processing. Radial velocity follow-up observations, however, were performed mainly by the 10-m Keck telescope in January 2010.
The companion CoRoT-21b is a Jupiter-like planet of 2.26±0.33 Jupiter masses and 1.30±0.14 Jupiter radii in an circular orbit of semimajor axis 0.0417±0.0011 AU and an orbital period of 2.72474±0.00014 days. The planetary bulk density is (1.36±0.48)·103 kg m−3, very similar to the bulk density of Jupiter, and follows an M1/3 −R relation like Jupiter. The F8IV star is a sub-giant star of 1.29±0.09 solar masses and 1.95±0.2 solar radii. The star and the planet exchange extreme tidal forces that will lead to orbital decay and extreme spin-up of the stellar rotation within 800 Myr if the stellar dissipation is Q∗/k2∗ ≤ 107.

Aims. We report the discovery of CoRoT-16b, a low density hot jupiter that orbits a faint G5V star (mV = 15.63) in 5.3523 ± 0.0002 days with slight eccentricity. A fit of the data with no a priori assumptions on the orbit leads to an eccentricity of 0.33 ± 0.1. We discuss this value and also derive the mass and radius of the planet.
Methods. We analyse the photometric transit curve of CoRoT-16 given by the CoRoT satellite, and radial velocity data from the HARPS and HIRES spectrometers. A combined analysis using a Markov chain Monte Carlo algorithm is used to get the system parameters.
Results. CoRoT-16b is a 0.535 −0.083/+0.085 MJ, 1.17 −0.14/+0.16 RJ hot Jupiter with a density of 0.44 −0.14/+0.21 g cm−3. Despite its short orbital distance (0.0618 ± 0.0015 AU) and the age of the parent star (6.73 ± 2.8 Gyr), the planet orbit exhibits significantly non-zero eccentricity.
This is very uncommon for this type of objects as tidal effects tend to circularise the orbit. This value is discussed taking into account the characteristics of the star and the observation accuracy.

The summer follow-up campaign on LRc07 and LRc08 fields was good, with 4 new planets + one from SRa04 awaiting publication. The CEST team is preparing the announcement of 5 new planets, in 2-3 papers (led resp. by Parviainen (CoRoT 27), Cabrera (CoRoT 28+29), Bordé (CoRoT 30+31)). They are mainly hot Jupiters (~Mjup and P<5d) but 2 are massive ones (P=10d and 3Mjup and P=4d and 10Mjup)
* The work is continuing on SRa01-0770 not confirmed with RV, re-observed in SRa05; though it is not sure it is a cluster member, it could be validated as planet anyway (Aigrain).
* The LAM team is progressing a lot on the validation procedure when RV is not conclusive, with the tool called PASTIS. Publication is on the way, and the analysis of a dozen of promising cases for which we could not conclude yet but have a lot of data. (Diaz)
* Magali is still working on the "mega paper" summarizing all candidates up to LRc08
* A review on CoRoT/exo for the Icarus special issue on exoplanet is foreseen for end of November
* The publications of the reobservation of CoRoT 7 and CoRoT 9 are being prepared, could be issued by the end of the year (Barros, Haywood, Hebrard)-
* CoRoT /exo program was presented this summer at COSPAR (Wuchterl), in Sagan school (Deleuil), in Beijing at IAU (Deleuil) and in Madrid EPSC (Deeg + Cabrera)
* MF mentions that a paper on host stars characterization is in progress with Magali and himself.