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Gliese 581e

Coordinates: Sky map 15h 19m 26s, −07° 43′ 20″
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Gliese 581e
Size comparison of Gliese 581e with Earth
(Based on selected hypothetical modeled compositions)[a]
Discovery[1]
Discovered byMayor et al.
Discovery siteLa Silla Observatory, Chile
Discovery date21 April 2009
Radial velocity
Orbital characteristics[2]
0.02799±0.0003 AU
Eccentricity0.012+0.015
−0.008
3.1481±0.0004 d
Inclination47°+15°
−13°
2454752.33 ± 0.05[3]
226°+91°
−55°
Semi-amplitude1.8±0.1 m/s
StarGliese 581
Physical characteristics[2]
Mass2.48+0.70
−0.42 M🜨

Gliese 581e /ˈɡliːzə/ or Gl 581e is an exoplanet orbiting within the Gliese 581 system, located 20.5 light-years (6.3 parsecs) away from Earth in the Libra constellation. It is the third planet discovered in the system (fourth if the disputed 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.[1]

With a minimum mass of about 1.9 Earth masses, Gliese 581e was the least massive exoplanet known around a normal star at the time of discovery in 2009, with only PSR B1257+12 A being less massive.[4][5] A 2024 study determined the orbital inclination of the planet, allowing its true mass to be determined, which is about 30% greater than the minimum mass at about 2.5 Earth masses.[2]

Gliese 581e completes an orbit around its parent star in 3.15 days. At an orbital distance of just 0.028 AU (4,200,000 km) from its parent star, it orbits further in than the habitable zone.[3] 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.[6]

See also

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Notes

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  1. ^ The estimated range of sizes in this image from 2009 is based on the planet's minimum mass. Since the true mass is now known to be somewhat greater, the sizes may be underestimated.

References

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  1. ^ a b Mayor, Michel; Bonfils, Xavier; Forveille, Thierry; et al. (2009). "The HARPS search for southern extra-solar planets, XVIII. An Earth-mass planet in the GJ 581 planetary system" (PDF). Astronomy and Astrophysics. 507 (1): 487–494. arXiv:0906.2780. Bibcode:2009A&A...507..487M. doi:10.1051/0004-6361/200912172. S2CID 2983930. Archived from the original (PDF) on 21 May 2009.
  2. ^ a b c von Stauffenberg, A.; Trifonov, T.; Quirrenbach, A.; et al. (2024-06-05). "The CARMENES search for exoplanets around M dwarfs. Revisiting the GJ 581 multi-planetary system with new Doppler measurements from CARMENES, HARPS, and HIRES". Astronomy & Astrophysics. arXiv:2407.11520. Bibcode:2024A&A...688A.112V. doi:10.1051/0004-6361/202449375. ISSN 0004-6361.
  3. ^ a b 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. 345 (6195): 440–444. arXiv:1407.1049. Bibcode:2014Sci...345..440R. doi:10.1126/science.1253253. PMID 24993348. S2CID 206556796.
  4. ^ Rincon, Paul; Amos, Jonathan (2009-04-21). "Lightest exoplanet is discovered". BBC. Archived from the original on 2009-04-24. Retrieved 2009-04-21.
  5. ^ Overbye, Dennis (April 21, 2009). "Astronomers Find Planet Closer to Size of Earth". New York Times. Archived from the original on March 12, 2017. Retrieved February 24, 2017.
  6. ^ Barnes, Rory; Jackson, Brian; Greenberg, Richard; Raymond, Sean N. (2009-06-09). "Tidal Limits to Planetary Habitability". The Astrophysical Journal. 700 (1): L30–L33. arXiv:0906.1785. Bibcode:2009ApJ...700L..30B. doi:10.1088/0004-637X/700/1/L30. S2CID 16695095.
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Media related to Gliese 581 e at Wikimedia Commons Discovery of smallest exoplanet yields 'extraordinary' find at Wikinews

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