CoRoT-2b

COROT-2b

Exoplanet		List of exoplanets
Size comparison of COROT-2b with Jupiter.
Parent star
Star		COROT-2
Constellation		Aquila
Right ascension	(α)	19^h 27^m 06.5^s[1]
Declination	(δ)	+1° 23′ 01.5″
Distance		930 ly (290 pc)
Spectral type		G7V[2]
Orbital elements
Semi-major axis	(a)	0.0281 ± 0.0005[1][3] AU
Eccentricity	(e)	0 (assumed)[1]
Orbital period	(P)	1.7429964 ± 0.0000017[1] d
Inclination	(i)	87.84 ± 0.10[1]°
Time of transit	(Tt)	2454237.53562 ± 0.00014[1] JD
Physical characteristics
Mass	(m)	3.31 ± 0.16[1] MJ
Radius	(r)	1.429 ± 0.047[1] RJ
Density	(ρ)	1310 ± 40[1] kg m^−3
Geometric Albedo	(Ag)	<0.12
Surface gravity	(g)	38.2[4] m/s²
Temperature	(T)	1537 ± 35[1]
Discovery information
Discovery date		2007-12-??, announced 2007-12-20
Discoverer(s)		Corot mission
Discovery method		Transit method
Other detection methods		Radial velocity, Reflection/emission modulations
Discovery site		Earth's orbit
Discovery status		Confirmed
Other designations
CoRoT-Exo-2b
Database references
Extrasolar Planets Encyclopaedia		data
SIMBAD		data
Exoplanet Archive		data
Open Exoplanet Catalogue		data

COROT-2b (formerly known as COROT-Exo-2b^[5]) is the second extrasolar planet to be detected by the French-led COROT mission, and orbits the star COROT-2 at a distance of 930 light years from Earth towards the constellation Aquila. Its discovery was announced on 20 December 2007.^[6] After its discovery via the transit method, its mass was confirmed via the radial velocity method.

Characteristics

The radial velocity trend of COROT-2, caused by the presence of COROT-2 b.

The planet is a large hot Jupiter, about 1.43 times the radius of Jupiter and approximately 3.3 times as massive. Its huge size is due to the intense heating from its parent star, which causes the outer layers of its atmosphere to bloat. The extremely large radius of the planet indicates that COROT-2b is very hot, estimated to be around 1500 K, even hotter than would be expected given its location close to its parent star. This fact may be a sign of tidal heating due to interactions with another planet.^[7] At Jupiter-like distances its radius would roughly be the same as Jupiter.^[8] The complete phase curve of this planet has been observed.^[9]

COROT-2b orbits its star approximately once every 1.7 days, and orbits the star in a prograde direction close to the star's equator.^[2] Its parent star is a G-type star, a bit cooler than the Sun but more active. It is located about 800 light-years from Earth.

It takes 125 minutes to transit its star.^[10]

As of August 2008, the COROT-2b spin-orbit angle (that is, the angle between the equator of the star and the plane of the planet orbit) was calculated by Bouchy et al. by means of the Rossiter–McLaughlin effect^[11] with a value of +7.2 ± 4.5 degrees.^[2]

References

1. Alonso et al. (2008). "Transiting exoplanets from the CoRoT space mission. II. CoRoT-Exo-2b: a transiting planet around an active G star". Astronomy and Astrophysics 482 (3): L21–L24. arXiv:0803.3207. Bibcode:2008A&A...482L..21A. doi:10.1051/0004-6361:200809431.
2. Bouchy, F.; Queloz, D.; Deleuil, M.; Loeillet, B.; Hatzes, A. P.; Aigrain, S.; Alonso, R.; Auvergne, M.; Baglin, A.; Barge, P.; Benz, W.; Bordé, P.; Deeg, H. J.; De La Reza, R.; Dvorak, R.; Erikson, A.; Fridlund, M.; Gondoin, P.; Guillot, T.; Hébrard, G.; Jorda, L.; Lammer, H.; Léger, A.; Llebaria, A.; Magain, P.; Mayor, M.; Moutou, C.; Ollivier, M.; Pätzold, M.; et al. (2008). "Transiting exoplanets from the CoRoT space mission". Astronomy and Astrophysics 482 (3): L25. arXiv:0803.3209. Bibcode:2008A&A...482L..25B. doi:10.1051/0004-6361:200809433.
3. The paper gives the semimajor axis as 6.70 ± 0.03 times the radius of the star, which is estimated at 0.902 ± 0.018 solar radii.
4. Calculated using Newtonian gravity: $\textstyle g=\frac{GM}{R^2}$
5. Schneider, J. (10 March 2009). "Change in CoRoT planets names". Exoplanets (Mailing list). Retrieved 2009-03-19.
6. "COROT surprises a year after launch". Retrieved 2007-12-21.
7. "CoRoT-exo-2 c?". Retrieved 2007-12-21.
8. Gibor Basri; Brown (20 August 2006). "Planetesimals to Brown Dwarfs: What is a Planet?". Annu. Rev. Earth Planet. Sci. 34: 193–216. arXiv:astro-ph/0608417. Bibcode:2006AREPS..34..193B. doi:10.1146/annurev.earth.34.031405.125058.
9. http://adsabs.harvard.edu/abs/2011sptz.prop80044C
10. "Predicted Transit Epochs: CoRoTExo2 b". TransitSearch (Oklo Corporation). Retrieved 2009-07-15. External link in |publisher= (help)
11. Joshua N. Winn (2008). "Measuring accurate transit parameters". Proceedings of the International Astronomical Union 4: 99. arXiv:0807.4929. doi:10.1017/S174392130802629X.

External links

Media related to COROT-2b at Wikimedia Commons

• COROT-Exo-2 light curve using differential photometry

Coordinates: 19^h 27^m 06.5^s, +01° 23′ 01.5″