GJ 27.1 b
GJ 27.1 b is a Neptune-like planet orbiting the M0.5 V star GJ 27.1 in the constellation Phoenix. It lies about 77 light-years from Earth and was discovered in 2014 using the radial velocity method.
Is GJ 27.1 b in the Habitable Zone?
GJ 27.1 b orbits inside the inner edge of the habitable zone of GJ 27.1. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of GJ 27.1: 0.132–0.341 AU (conservative: 0.167–0.324 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
See the full interactive habitable-zone view in the Exoplanet Explorer app ›
Orbit and Year Length
A year on GJ 27.1 b — one full orbit around GJ 27.1 — lasts 15.8 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.101 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.08).
How Was GJ 27.1 b Discovered?
GJ 27.1 b was discovered in 2014 using the radial velocity method, with observations from Multiple Observatories.
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 27.1 b?
GJ 27.1 b is 77.0 light-years (23.6 parsecs) from Earth. Light arriving here tonight left the planet around the year 1949. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 1,355,200 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 27.1 b scores 0.49, ranking #259 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: GJ 27.1
GJ 27.1
- Spectral type
- M0.5 V
- Surface temperature
- 3,542 K (Sun: 5,772 K)
- Mass
- 0.53 M☉
- Luminosity
- 0.0260 L☉
Planetary System
GJ 27.1 b is the only planet known to orbit GJ 27.1 so far.
GJ 27.1 b — Complete Data
| Mass (best estimate) | 13.00 Earth masses |
|---|---|
| Orbital period | 15.82 days |
| Orbital distance | 0.101 AU |
| Eccentricity | 0.080 |
| Earth Similarity Index | 0.49 |
| Distance from Earth | 77.0 light-years (23.6 parsecs) |
| Constellation | Phoenix |
| Discovery method | Radial Velocity |
| Discovery facility | Multiple Observatories |
| Discovery year | 2014 |
Data: NASA Exoplanet Archive, last updated 2019-10-04. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About GJ 27.1 b
Is GJ 27.1 b habitable?
No — GJ 27.1 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is GJ 27.1 b?
GJ 27.1 b is about 77 light-years from Earth in the constellation Phoenix. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 1,355,200 years to get there.
How long is a year on GJ 27.1 b?
One orbit around GJ 27.1 takes 15.8 Earth days — short enough that 23 of its years would fit into one Earth year.
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