Gliese 581 e

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Gliese 581 e
Extrasolar planet List of extrasolar planets
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
Semimajor axis (a) 0.02815 ± 0.00006[1] AU
Eccentricity (e) 0.00 ± 0.06[1]
Orbital period (P) 3.1490 ± 0.0002[1] d
Time of periastron (T0) 2454752.33 ± 0.05[1] JD
Semi-amplitude (K) 1.7 ± 0.2[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 /ˈɡlzə/ or Gl 581 e is an extrasolar planet found around Gliese 581, a red dwarf star approximately 20.5 light-years away from Earth in the constellation of Libra. It is the third planet discovered in the system (fourth if the refuted planet candidate Gliese 581 d 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.[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[edit]

References[edit]

  1. ^ a b c d e f g Robertson, Paul; Mahadevan, Suvrath; Endl, Michael; Roy, Arpita (3 July 2014). "Stellar activity masquerading as planets in the habitable zone of the M dwarf Gliese 581". Science (journal). arXiv:1407.1049. doi:10.1126/science.1253253. 
  2. ^ a b c Mayor, M.; Bonfils, X.; Forveille, T.; Delfosse, X.; Udry, S.; Bertaux, J.-L.; Beust, H.; Bouchy, F. et al. (2009). "The HARPS search for southern extra-solar planets, XVIII. An Earth-mass planet in the GJ 581 planetary system". Astronomy and Astrophysics 507 (1): 487–494. arXiv:0906.2780. Bibcode:2009A&A...507..487M. doi:10.1051/0004-6361/200912172. 
  3. ^ Barnes, Rory; Jackson, Brian; Greenberg, Richard; Raymond, Sean N. (2009-06-09). "Tidal Limits to Planetary Habitability". The Astrophysical Journal 700: L30–L33. arXiv:0906.1785v1. Bibcode:2009ApJ...700L..30B. doi:10.1088/0004-637X/700/1/L30. 
  4. ^ Rincon, Paul; Amos, Jonathan (2009-04-21). "Lightest exoplanet is discovered". BBC. Retrieved 2009-04-21. 
  5. ^ Overbye, Dennis (April 21, 2009). "Astronomers Find Planet Closer to Size of Earth". New York Times. 

External links[edit]

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

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