GJ 1265 b
GJ 1265 b is a super-Earth orbiting the M4.5 V star GJ 1265 in the constellation Aquarius. It lies about 33 light-years from Earth and was discovered in 2018 using the radial velocity method.
Is GJ 1265 b in the Habitable Zone?
GJ 1265 b orbits inside the inner edge of the habitable zone of GJ 1265. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of GJ 1265: 0.049–0.130 AU (conservative: 0.063–0.123 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 1265 b — one full orbit around GJ 1265 — lasts 3.65 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.026 AU — closer to its star than Mercury is to the Sun. Its orbit is nearly circular (eccentricity 0.040).
How Was GJ 1265 b Discovered?
GJ 1265 b was discovered in 2018 using the radial velocity method, with observations from Calar Alto 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 1265 b?
GJ 1265 b is 33.4 light-years (10.3 parsecs) from Earth. Light arriving here tonight left the planet around the year 1993. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 587,840 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 1265 b scores 0.42, ranking #416 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: GJ 1265
GJ 1265
- Spectral type
- M4.5 V
- Surface temperature
- 3,236 K (Sun: 5,772 K)
- Mass
- 0.18 M☉
- Radius
- 0.19 R☉
- Luminosity
- 0.0036 L☉
Planetary System
GJ 1265 b is the only planet known to orbit GJ 1265 so far.
GJ 1265 b — Complete Data
| Mass (best estimate) | 7.40 Earth masses |
|---|---|
| Orbital period | 3.65 days |
| Orbital distance | 0.026 AU |
| Eccentricity | 0.040 |
| Earth Similarity Index | 0.42 |
| Distance from Earth | 33.4 light-years (10.3 parsecs) |
| Constellation | Aquarius |
| Discovery method | Radial Velocity |
| Discovery facility | Calar Alto Observatory |
| Discovery year | 2018 |
Data: NASA Exoplanet Archive, last updated 2018-12-03. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About GJ 1265 b
Is GJ 1265 b habitable?
No — GJ 1265 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is GJ 1265 b?
GJ 1265 b is about 33 light-years from Earth in the constellation Aquarius. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 587,840 years to get there.
How long is a year on GJ 1265 b?
One orbit around GJ 1265 takes 3.7 Earth days — short enough that 100 of its years would fit into one Earth year.
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