Gliese 876 e

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 by	Rivera et al.
Discovery date	June 23, 2010
Detection method	Doppler spectroscopy
Orbital characteristics[2][3]
Epoch BJD 2,450,602.09311
Semi-major axis	0.3355+0.0019 −0.0011 AU
Eccentricity	0.0545+0.0069 −0.022
Orbital period (sidereal)	123.55+1.0 −0.59 d
Mean anomaly	50.3°+46° −86.8°
Inclination	56.7°+1.0° −0.99°
Argument of periastron	240°+23° −50°
Semi-amplitude	3.49±0.23 m/s
Star	Gliese 876
Physical characteristics[3]
Mass	16.0±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]