Gliese 581c
| Exoplanet | List of exoplanets | |
|---|---|---|
 (Based on selected hypothetical modeled compositions) |
||
| Parent star | ||
| Star | Gliese 581 | |
| Constellation | Libra | |
| Right ascension | (α) | 15h 19m 26s |
| Declination | (δ) | −07° 43′ 20″ |
| Distance | 20.37 ly (6.26 pc) |
|
| Spectral type | M3V | |
| Mass | (m) | 0.31 M☉ |
| Radius | (r) | 0.29 R☉ |
| Temperature | (T) | 3480 ± 48 K |
| Metallicity | [Fe/H] | -0.33 ± 0.12 |
| Age | 7 – 11 Gyr | |
| Orbital elements | ||
| Semi-major axis | (a) | 0.0721 ± 0.0003AU |
| Eccentricity | (e) | 0.00 ± 0.06 |
| Orbital period | (P) | 12.914 ± 0.002d |
| Time of periastron | (T0) | 2454759.2 ± 0.1JD |
| Semi-amplitude | (K) | 3.3 ± 0.2m/s |
| Physical characteristics | ||
| Minimum mass | (m sin i) | 5.5 ± 0.3M⊕ |
| Stellar flux | (F⊙) | 2.5 ⊕ |
| Discovery information | ||
| Discovery date | April 4, 2007 April 24, 2007 (announced) |
|
| Discoverer(s) | Stéphane Udry et al. | |
| Discovery method | Radial velocity | |
| Discovery site | La Silla Observatory | |
| Discovery status | Published | |
| Database references | ||
| Extrasolar Planets Encyclopaedia |
data | |
| SIMBAD | data | |
| Exoplanet Archive | data | |
| Open Exoplanet Catalogue | data | |
Gliese 581c /ˈɡliːzə/ or Gl 581c is a planet orbiting within the Gliese 581 planetary system. It is the second planet discovered in the system and the third in order from the star. With a mass at least 5.5 times that of the Earth, it is classified as a super-Earth (a category of planets from 5 to 10 Earth masses).
Gliese 581c gained interest from astronomers because it was reported to be the first potentially Earth-like planet in the habitable zone of its star, with a temperature right for liquid water on its surface, and by extension, potentially capable of supporting extremophile forms of Earth-like life. However, further research casts doubt upon the planet's habitability. It is tidally locked (always faces the parent star with the same face) so if life had a chance to emerge, the best hope of survival would be "the Goldilocks zone."
In astronomical terms, the Gliese 581 system is relatively close to Earth, at 20.37 light-years (192 trillion km or 119 trillion miles) in the direction of the constellation of Libra. This distance, along with the declination and right ascension coordinates, give its exact location in our galaxy.
The team released a paper of their findings dated April 27, 2007, published in the July 2007 journal Astronomy and Astrophysics. At the time of discovery, it was reported to be the first potentially Earth-like planet in the habitable zone of its star and the smallest known extrasolar planet around a main-sequence star but on April 21, 2009, another planet orbiting Gliese 581, Gliese 581e, with an approximate mass of 1.9 Earth masses, was announced. In the paper, they also announced the discovery of another planet in the system, Gliese 581d, with a minimum mass of 7.7 Earth masses and a semi-major axis of 0.25 astronomical units.
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