Gliese 581e
| 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″ |
| Apparent magnitude | (mV) | 10.56 to 10.58 |
| Distance | 20.37 ± 0.17 ly (6.2 ± 0.1 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) | 0.02815 ± 0.00006AU |
| Eccentricity | (e) | 0.00 ± 0.06 |
| Orbital period | (P) | 3.1490 ± 0.0002d |
| Time of periastron | (T0) | 2454752.33 ± 0.05JD |
| Semi-amplitude | (K) | 1.7 ± 0.2m/s |
| Physical characteristics | ||
| Minimum mass | (m sin i) | 1.7 ± 0.2M⊕ |
| Stellar flux | (F⊙) | 16.4 ⊕ |
| Discovery information | ||
| Discovery date | 21 April 2009 | |
| Discoverer(s) | Mayor et al. | |
| Discovery method | Radial velocity | |
| Discovery site | La Silla Observatory, Chile | |
| Discovery status | Published | |
| Database references | ||
| Extrasolar Planets Encyclopaedia |
data | |
| SIMBAD | data | |
| Exoplanet Archive | data | |
| Open Exoplanet Catalogue | data | |
Gliese 581e /ˈɡliːzə/ or Gl 581e is an extrasolar planet orbiting within the Gliese 581 planetary system, located approximately 20.4 light-years away from Earth in the Libra constellation. It is the third planet discovered in the system (fourth if the refuted planet candidate Gliese 581d is included) and the first in order from the star.
The planet was discovered by an Observatory of Geneva team led by Michel Mayor, using the HARPS instrument on the European Southern Observatory 3.6 m (140 in) telescope in La Silla, Chile. The discovery was announced on 21 April 2009. Mayor's team employed the radial velocity technique, in which the orbit size and mass of a planet are determined based on the small perturbations it induces in its parent star's orbit via gravity.
At a minimum mass of 1.7 Earth masses, it is one of the least massive extrasolar planets discovered around a normal star, and relatively close in mass to Earth. At an orbital distance of just 0.03 AU (4,500,000 km) from its parent star, however, it orbits further in than the habitable zone. It is unlikely to possess an atmosphere due to its high temperature and strong radiation from the star. Although scientists think it probably has a rocky surface similar to Earth, it is also likely to experience intense tidal heating similar to (and likely more intense than) that affecting Jupiter's moon Io. Gliese 581e completes an orbit of its sun in approximately 3.15 days.
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