Gliese 876 b

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Exoplanet
Gliese 876 b

Artist's impression of Gliese 876 b and hypothetical moons with a view of the central star

Artist's impression of Gliese 876 b and hypothetical moons with a view of the central star
Constellation Aquarius
Position
equinox : J2000.0
Right ascension 22h 53m 16.73352s
declination −14 ° 15 ′ 49.3186 ″
Orbit data
Central star Peter 876
Major semi-axis 0.214 ± 0.001 AU
eccentricity 0.040   +0.021−0.004
Period of circulation 61.082   + 0.006−0.010 d
Further data
Minimum dimensions 760.9 ± 1.0 M ♁
distance 4.660 ± 0.004 pc
history
discovery Marcy et al. , Delfosse et al.
Date of discovery 1998
Catalog names
GJ 876 b, IL Aqr b, HIP 113020 b

Gliese b 876 a is Exoplanet which the 15 light-years from the sun away red dwarf gliese 876 orbits. It is the second outermost known planet in the star's planetary system .

discovery

The planet was discovered independently in June 1998 by two teams of astronomers led by Geoffrey Marcy and Xavier Delfosse . The discovery was made using the radial velocity method . Gliese 876 b was the first known exoplanet to orbit a red dwarf.

properties

Gliese 876 b orbits its central star at a distance of about 0.214 AU in just over 61 days. Its minimum mass is a little more than two masses of Jupiter . With its inner neighbor Gliese 876 c and Gliese 876 e circling further out , it is in a Laplace resonance : on four revolutions of Gliese 876 c there are two of Gliese 876 b and one of Gliese 876 e. The three planets are comparable to the three Jupiter moons Io , Europa and Ganymede , which are also in a Laplace resonance.

It is believed that the three outer planets of Gliese 876 were formed at a greater distance from the star and then migrated into their current orbits. The orbit inclination of Gliese 876 b is probably 59 °. The major orbit half-axis is about 0.208317 AU smaller than that of the planet Mercury (0.387 AU) in the solar system . Because of the low luminosity of the central star, Gliese 876 b is still in its habitable zone .

Due to its minimum mass, it can be assumed that Gliese 876 b is a gas planet like Jupiter in the solar system. Assuming a Jupiter-like atmosphere, its atmosphere is probably too cold for silicate clouds, but too warm for water to condense. It thus appears cloudless.

Individual evidence

  1. ↑ SIMBAD: Gliese 876. Retrieved July 4, 2015 .
  2. ↑ a b c d The CARMENES search for exoplanets around M dwarfs. First visual-channel radial-velocity measurements and orbital parameter updates of seven M-dwarf planetary systems. (PDF) October 4, 2017, p. 17 , accessed on January 18, 2018 . doi : 10.1051 / 0004-6361 / 201731442 , arxiv : 1710.01595
  3. ^ Marcy, Geoffrey W. et al .: A Planetary Companion to the Nearby M4 Dwarf, Gliese 876 . arxiv : astro-ph / 9807307 .
  4. ↑ Delfosse, X. et al .: The closest extrasolar planet: A giant planet around the M4 dwarf Gl 876 . arxiv : astro-ph / 9808026 .
  5. ↑ a b Rivera, Eugenio J. et al .: The Lick-Carnegie Exoplanet Survey: A Uranus-mass Fourth Planet for GJ 876 in an Extrasolar Laplace Configuration . arxiv : 1006.4244 .
  6. ↑ Gerlach, E .; Haghighipour, N .: Can GJ 876 host four planets in resonance? arxiv : 1202.5865 .
  7. ^ Jones, Barrie W. et al .: Prospects for Extrasolar "Earths" in Habitable Zones . arxiv : astro-ph / 0503178 .
  8. ↑ Sudarsky, David et al .: Theoretical Spectra and Atmospheres of Extrasolar Giant Planets . arxiv : astro-ph / 0210216 .