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GJ 876 e

Neptune-like Aquarius

GJ 876 e is a Neptune-like planet orbiting GJ 876 in the constellation Aquarius. It lies about 15 light-years from Earth and was discovered in 2010 using the radial velocity method.

14.6×Earth mass
124 dOrbital period
0.30Earth similarity
15 lyDistance
2010Discovered

Is GJ 876 e in the Habitable Zone?

The position of GJ 876 e relative to the habitable zone of GJ 876 cannot be precisely determined from the available orbital data.

Orbit and Year Length

A year on GJ 876 e — one full orbit around GJ 876 — lasts 124.3 Earth days, between the years of Mercury (88 days) and Earth (365 days). It orbits at an average distance of 0.334 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.06).

How Was GJ 876 e Discovered?

GJ 876 e was discovered in 2010 using the radial velocity method, with observations from W. M. Keck Observatory.

The radial velocity method measures the subtle wobble of a star caused by the gravitational pull of an orbiting planet, visible as periodic shifts in the star's light spectrum. The size of the wobble reveals the planet's minimum mass.

How Far Away Is GJ 876 e?

GJ 876 e is 15.2 light-years (4.7 parsecs) from Earth. Light arriving here tonight left the planet around the year 2011. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 267,520 years to make the journey.

Earth Similarity Index

The Earth Similarity Index (ESI) scores how physically similar a planet is to Earth, from 0 to 1, based on radius, density, escape velocity and surface temperature. GJ 876 e scores 0.30, ranking #1,532 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.

The Host Star: GJ 876

GJ 876

Mass
0.32 M☉
Radius
0.30 R☉
Luminosity
0.0124 L☉
Age
1.0 billion years (Sun: 4.6)

The GJ 876 Planetary System

GJ 876 e is one of 4 known planets in the GJ 876 system. Its siblings:

GJ 876 e — Complete Data

Mass14.60 Earth masses (0.046 Jupiter masses)
Orbital period124.26 days
Orbital distance0.334 AU
Eccentricity0.055
Earth Similarity Index0.30
Distance from Earth15.2 light-years (4.7 parsecs)
ConstellationAquarius
Discovery methodRadial Velocity
Discovery facilityW. M. Keck Observatory
Discovery year2010

Data: NASA Exoplanet Archive, last updated 2014-08-27. Earth Similarity Index: PHL @ UPR Arecibo.

Frequently Asked Questions About GJ 876 e

Is GJ 876 e habitable?

GJ 876 e is not known to orbit within the habitable zone of GJ 876, and as a Neptune-like planet it is an unlikely candidate for life as we know it.

How far away is GJ 876 e?

GJ 876 e is about 15 light-years from Earth in the constellation Aquarius. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 267,520 years to get there.

How long is a year on GJ 876 e?

One orbit around GJ 876 takes 124.3 Earth days.

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