| Extrasolar planet | List of extrasolar planets | |
|---|---|---|
(Based on selected hypothetical modeled compositions) |
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| Parent star | ||
| Star | Gliese 581 | |
| Constellation | Libra | |
| Right ascension | (α) | 15h 19m 26s |
| Declination | (δ) | −07° 43′ 20″ |
| Apparent magnitude | (mV) | 10.55 |
| Distance | 20.3 ± 0.3 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 Epoch JD 2451409.762[1] |
||
| Semimajor axis | (a) | 0.0284533 ± 0.0000023[1] AU |
| Eccentricity | (e) | 0[1] |
| Orbital period | (P) | 3.14867 ± 0.00039[1] d (0.0086 y) |
| (75.57 h) | ||
| Mean anomaly | (M) | 267 ± 40[1]° |
| Semi-amplitude | (K) | 1.66 ± 0.19[1] m/s |
| Physical characteristics | ||
| Minimum mass | (m sin i) | 1.7 ± 0.2[1] M⊕ |
| Discovery information | ||
| Discovery date | 21 April 2009 | |
| Discoverer(s) | Mayor et al. | |
| Detection method | Radial velocity | |
| Discovery site | La Silla Observatory, Chile | |
| Discovery status | Published[2] | |
| Database references | ||
| Extrasolar Planets Encyclopaedia |
data | |
| SIMBAD | data | |
Gliese 581 e ( /ˈɡliːzə/) or Gl 581 e is an extrasolar planet found around Gliese 581, an M3V red dwarf star approximately 20.5 light-years away from Earth in the constellation of Libra. It is the fourth planet discovered in the system 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.[2]
At a minimum mass of 1.7 Earth masses,[1] it is the least-massive extrasolar planet discovered around a normal star, and thus the closest in mass to Earth. At an orbital distance of just 0.03 AU 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.[3] Gliese 581 e completes an orbit of its sun in approximately 3.15 days.[2][4][5]
Media related to [//commons.wikimedia.org/wiki/Category:Gliese_581_e Gliese 581 e] at Wikimedia Commons
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