COROT-7c
Encyclopedia
COROT-7c is an extrasolar planet
which orbits the G-type main sequence
star
COROT-7, located approximately 489 light years away in the constellation
Monoceros
. It's either a super-Earth
or a Neptune
-like planet, orbiting at 0.046 AU
from the star, taking 3.7 days or 89 hours to make one round trip around the star.
mission. However, unlike COROT-7b, it was not detected by the transit method from the COROT
satellite, but only by the radial velocity method using HARPS from La Silla Observatory
, Chile
. A posteriori search of transits of COROT-7c in the lightcurve of the star COROT-7 yielded a negative result, confirming the planet is not transiting. As a consequence no radius measurement is available, and no density and structure models of the planet can be established.
-like planet. Chances are high that planet's rotation is tidally locked to the orbital period, with one side of the planet always facing the star COROT-7 and the other one in permanent darkness.
A possible third planet, COROT-7d, may be present in the system, but pending further observations its status remains unconfirmed. If this planet is confirmed, strong mutual gravitational forces
could be exchanged between these planets, leading to powerful tidal forces.
Extrasolar planet
An extrasolar planet, or exoplanet, is a planet outside the Solar System. A total of such planets have been identified as of . It is now known that a substantial fraction of stars have planets, including perhaps half of all Sun-like stars...
which orbits the G-type main sequence
Main sequence
The main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell...
star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
COROT-7, located approximately 489 light years away in the constellation
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
Monoceros
Monoceros
Monoceros is a faint constellation on the celestial equator. Its name is Greek for unicorn. Its definition is attributed to the 17th-century Dutch cartographer Petrus Plancius. It is bordered by Orion to the west, Gemini to the north, Canis Major to the south and Hydra to the east...
. It's either a super-Earth
Super-Earth
A super-Earth is an extrasolar planet with a mass higher than Earth's, but substantially below the mass of the Solar System's gas giants. The term super-Earth refers only to the mass of the planet, and does not imply anything about the surface conditions or habitability...
or a Neptune
Neptune
Neptune is the eighth and farthest planet from the Sun in the Solar System. Named for the Roman god of the sea, it is the fourth-largest planet by diameter and the third largest by mass. Neptune is 17 times the mass of Earth and is slightly more massive than its near-twin Uranus, which is 15 times...
-like planet, orbiting at 0.046 AU
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
from the star, taking 3.7 days or 89 hours to make one round trip around the star.
Discovery
The discovery of the planet was announced in February 2009, during the First Corot Symposium. It was discovered during the follow-up started in order to confirm the existence of COROT-7b, a super-Earth uncovered by the COROTCorot
Corot may refer to:* Jean-Baptiste-Camille Corot, French landscape painter * COROT, a space mission with the dual aims of finding extrasolar planets and performing asteroseismology* COROT-7, a dwarf star in the Monoceros constellation...
mission. However, unlike COROT-7b, it was not detected by the transit method from the COROT
Corot
Corot may refer to:* Jean-Baptiste-Camille Corot, French landscape painter * COROT, a space mission with the dual aims of finding extrasolar planets and performing asteroseismology* COROT-7, a dwarf star in the Monoceros constellation...
satellite, but only by the radial velocity method using HARPS from La Silla Observatory
La Silla Observatory
La Silla Observatory is an astronomical observatory in Chile with three telescopes built and operated by the European Southern Observatory organisation, and several others are partly maintained by ESO...
, Chile
Chile
Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...
. A posteriori search of transits of COROT-7c in the lightcurve of the star COROT-7 yielded a negative result, confirming the planet is not transiting. As a consequence no radius measurement is available, and no density and structure models of the planet can be established.
Characteristics
Like COROT-7b, the mass of COROT-7c is weakly costrained, since the radial velocity data is noisy due to the presence of stellar activity. Published mass measurements range from 8.4 Earth masses to 13.5 Earth masses, passing through 12.4 Earth masses and 13.1 Earth masses. This mass range encompasses the Super-Earths to Neptunes transition, so the nature of COROT-7c, either a rocky planet or an ice giant, remains unclear. However, if the larger mass estimates are correct, COROT-7c is probably a hot UranusUranus
Uranus is the seventh planet from the Sun. It has the third-largest planetary radius and fourth-largest planetary mass in the Solar System. It is named after the ancient Greek deity of the sky Uranus , the father of Cronus and grandfather of Zeus...
-like planet. Chances are high that planet's rotation is tidally locked to the orbital period, with one side of the planet always facing the star COROT-7 and the other one in permanent darkness.
A possible third planet, COROT-7d, may be present in the system, but pending further observations its status remains unconfirmed. If this planet is confirmed, strong mutual gravitational forces
Gravitational Forces
Gravitational Forces is an album by Texas-based country/folk singer-songwriter Robert Earl Keen. It was first released in the United States on August 7, 2001 on Lost Highway....
could be exchanged between these planets, leading to powerful tidal forces.