Gliese 581 e

Gliese 581 e

Extrasolar planet		List of extrasolar planets
Size comparison of Gliese 581 e with Earth. (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)	10.55
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.
Discovery 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]

Artist concept of Gliese 581 e

At a minimum mass of 1.7 Earth masses,^[1] it is one of the least-massive extrasolar planet discovered around a normal star, and relatively close 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]

See also

• PSR B1257+12 A — a much smaller pulsar planet.
• Habitability of red dwarf systems

References

External links

Media related to Gliese 581 e at Wikimedia Commons News related to Discovery of smallest exoplanet yields 'extraordinary' find at Wikinews

• Lightest exoplanet yet discovered European Southern Observatory press release
• Scientists discover a nearly Earth-sized planet
• Publications at Exoplanet.eu

v t e Gliese 581 system Star Gliese 581 Planets Gliese 581 e Gliese 581 b Gliese 581 c Gliese 581 g Gliese 581 d Gliese 581 f Messages A Message From Earth Hello From Earth Book:Gliese 581 Category:Gliese 581 Portal:Astronomy

Coordinates: 15^h 19^m 26^s, −07° 43′ 20″