Gliese 876 e is an exoplanet orbiting the star Gliese 876 in the constellation of Aquarius. It is in a 1:2:4 Laplace resonance with the planets Gliese 876 c and Gliese 876 b: for each orbit of planet e, planet b completes two orbits and planet c completes four. This configuration is the second known example of a Laplace resonance after Jupiter's moons Io, Europa and Ganymede.[1] Its orbit takes 124 days to complete.

Gliese 876 e
An artist's impression of Gliese 876 e
Discovery[1]
Discovered byRivera et al.
Discovery dateJune 23, 2010
Doppler spectroscopy
Orbital characteristics[2][3]
Epoch BJD 2,450,602.09311
0.3355+0.0019
−0.0011
 AU
Eccentricity0.0545+0.0069
−0.022
123.55+1.0
−0.59
 d
50.3°+46°
−86.8°
Inclination56.7°+1.0°
−0.99°
240°+23°
−50°
Semi-amplitude3.49±0.23 m/s
StarGliese 876
Physical characteristics[3]
Mass16.0±1.0 M🜨
The orbits of the planets of Gliese 876. Gliese 876 e is the furthest planet from the star.

Gliese 876 e has a mass similar to that of the planet Uranus. Its orbit takes 124 days to complete, or roughly one third of a year. While the orbital period is longer than that of Mercury around the Sun, the lower mass of the host star relative to the Sun means the planet's orbit has a slightly smaller semimajor axis. Unlike Mercury, Gliese 876 e has a nearly circular orbit with an eccentricity of 0.055 ± 0.012.[1]

This planet, like b and c, has likely migrated inward.[4]

References

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  1. ^ a b c Rivera, Eugenio J.; et al. (July 2010). "The Lick-Carnegie Exoplanet Survey: A Uranus-mass Fourth Planet for GJ 876 in an Extrasolar Laplace Configuration". The Astrophysical Journal. 719 (1): 890–899. arXiv:1006.4244. Bibcode:2010ApJ...719..890R. doi:10.1088/0004-637X/719/1/890. S2CID 118707953.
  2. ^ Millholland, Sarah; et al. (2018). "New Constraints on Gliese 876—Exemplar of Mean-motion Resonance". The Astronomical Journal. 155 (3) 106. arXiv:1801.07831. Bibcode:2018AJ....155..106M. doi:10.3847/1538-3881/aaa894. S2CID 119011611.
  3. ^ a b Moutou, C.; Delfosse, X.; et al. (July 2023). "Characterizing planetary systems with SPIRou: M-dwarf planet-search survey and the multiplanet systems GJ 876 and GJ 1148". Astronomy & Astrophysics. arXiv:2307.11569.
  4. ^ Gerlach, Enrico; Haghighipour, Nader (2012). "Can GJ 876 host four planets in resonance?". Celestial Mechanics and Dynamical Astronomy. 113 (1): 35–47. arXiv:1202.5865. Bibcode:2012CeMDA.113...35G. doi:10.1007/s10569-012-9408-0. S2CID 254381557.