Transiting Exoplanets From The CoRoT Space Mission XXIII. CoRoT-21B: A Doomed Large Jupiter Around A Faint Subgiant Star




Patzold, M.
Endl, M.
Csizmadia, S.
Gandolfi, D.
Jorda, L.
Grziwa, S.
Carone, L.
Pasternacki, T.
Aigrain, S.
Almenara, J. M.

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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 semi-major 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) x 10(3) kg m(-3), very similar to the bulk density of Jupiter, and follows an M-1/3 - 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.


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Pätzold, M., M. Endl, Sz Csizmadia, D. Gandolfi, L. Jorda, S. Grziwa, Ludmila Carone et al. >Transiting exoplanets from the CoRoT space mission-XXIII. CoRoT-21b: a doomed large Jupiter around a faint subgiant star.> Astronomy & Astrophysics, Vol. 545 (Sep., 2012): A6.