COROT-7

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COROT-7
Morgan-Keenan spectral classification zoom.png

COROT-7 is a G9V class star somewhat less massive than the Sun (G2V)
Observation data
Epoch J2000      Equinox J2000
Constellation Monoceros[1]
Right ascension 06h 43m 49.0s[1]
Declination −01° 03′ 46.0″[1]
Apparent magnitude (V) 11.668[1]
Characteristics
Spectral type G9V[1]
Astrometry
Radial velocity (Rv) +31.174 ± 0.0086[1] km/s
Distance 489 ± 65[1] ly
(150 ± 20[1] pc)
Absolute magnitude (MV) 5.78[1]
Details
Mass 0.91 ± 0.03[1] M
Radius 0.82 ± 0.04[1] R
Surface gravity (log g) 4.47 ± 0.10[1] cgs
Temperature 5250 ± 60[1] K
Metallicity [M/H] = 0.12 ± 0.06[1]
Rotation ~23 days[2]
Rotational velocity (v sin i) <3.5[1] km/s
Age (1.2 – 2.3) × 109[1] years
Other designations
2MASS J06434947-0103468, TYC 4799-1733-1, GSC 04799-01733
Database references
SIMBAD data
Exoplanet Archive data
Extrasolar Planets
Encyclopaedia
data

Coordinates: Sky map 06h 43m 49.0s, −01° 03′ 46.0″

COROT-7 (TYC 4799-1733-1) is a G-type main sequence star, slightly smaller and cooler than the Sun. It has an apparent magnitude 11.67, fainter than Proxima Centauri (mag. 11.05), the nearest star to the Sun. This star is located in the Monoceros constellation.[3]

Location and properties[edit]

The star is located in the LRa01 field of view of the COROT spacecraft. It is about 500 light years from earth. According to the project website, this field is in the Monoceros constellation.[3] Published data[4] lists the stellar properties as being a G9V yellow dwarf with a temperature of 5250 K, a radius of about 82% of the Sun and a mass of about 91% of the Sun.[1] But other sources have been known to list it is a (K0V) orange dwarf.[5] The metallicity, i.e. the quantity [M/H] of the star, which is the base-10 logarithm of the ratio of the star's metal abundance (given by the ratio of metals to hydrogen) to that of the Sun is 0.12 ± 0.06. The star is estimated to be about 150 parsecs away and with an age in the range 1.2 – 2.3 billion years, is younger than our own star which has an age of 4.6 billion years.[1] The rotation period of the star, inferred by the lightcurve obtained by COROT, is around 23 days.

Planetary system[edit]

The star is reported to be orbited by the super-Earth extrasolar planets COROT-7b and COROT-7c, both discovered in 2009.[2] The existence of a possible third planet COROT-7d, detected in a published study,[6] remains unconfirmed. The discovery of the inner planet was made using the astronomical transit method by the COROT program. CoRoT-7b is notable for its small size.[7]

The COROT-7 planetary system[2]
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
Eccentricity Inclination Radius
b from 2.3 to 8.5 M 0.0172 ± 0.00029 0.853585 ± 0.000024 0 1.58 ± 0.1 R
c from 8.4 to 13.5[8] M 0.046 3.698 ± 0.003 0
d (unconfirmed) 16.8[8] M 0.08 9.021 ± 0.019 0

This star was reported to have stellar activity, making the confirmation process for CoRoT-7b more difficult. In fact, mass estimates are affected by large uncertainty due to stellar activity, that perturbs the radial velocity measurements needed to "weigh" the planets.[2][9]

See also[edit]

  • COROT - an operational French-led ESA planet-hunting mission spacecraft, launched in 2006

References[edit]

  1. ^ a b c d e f g h i j k l m n o p q r A. Léger, D. Rouan, J. Schneider, P. Barge, M. Fridlund et al (2009). "Transiting exoplanets from the CoRoT space mission VIII. CoRoT-7b: the first Super-Earth with measured radius". Astronomy and Astrophysics 506: 287–302. arXiv:0908.0241. Bibcode:2009A&A...506..287L. doi:10.1051/0004-6361/200911933. 
  2. ^ a b c d Queloz, D., Bouchy, F., Moutou, C., Hatzes, A., Hebrard, G. et al (2009). "The CoRoT-7 planetary system: two orbiting Super-Earths" (PDF). Astronomy and Astrophysics 506: 303. Bibcode:2009A&A...506..303Q. doi:10.1051/0004-6361/200913096.  Also available from exoplanet.eu
  3. ^ a b Rouan et al. (February 3, 2009). "CoRoT-exo-7b Has CoRoT discovered the first transiting Super-Earth around a main sequence star?" (PDF). Corot Symposium - Paris. Retrieved 2009-07-05. 
  4. ^ Bruntt; Deleuil; Fridlund; Alonso; Bouchy; Hatzes; Mayor; Moutou et al. (2010). "Improved stellar parameters of CoRoT-7". arXiv:1005.3208 [astro-ph.SR].
  5. ^ Jean Schneider. "Star : CoRoT-7". The Extrasolar Planets Encyclopaedia. Retrieved 2009-12-26. 
  6. ^ Hatzes; Dvorak; Wuchterl; Guterman; Hartmann; Fridlund; Gandolfi; Guenther et al. (2010). "An Investigation into the Radial Velocity Variations of CoRoT-7". arXiv:1006.5476 [astro-ph.SR].
  7. ^ "Super-Earth found! The smallest transiting extrasolar planet ever discovered". Paris Observatory. February 2009. Retrieved 2009-02-04. 
  8. ^ a b Assuming CoRoT-7b and CoRoT-7c are coplanar orbits
  9. ^ "CoRoT-Exo-7b: Confirming the first transiting rocky planet". Retrieved 2010-08-23. 

External links[edit]