GJ 1252 b
GJ 1252 b is a terrestrial planet orbiting the M3 star GJ 1252 in the constellation Telescopium. It lies about 66 light-years from Earth and was discovered in 2020 using the transit method.
How Big Is GJ 1252 b?
GJ 1252 b has a radius of 1.19 times that of Earth. Its mass is 1.3 times that of Earth, giving it a density of 4.20 g/cm³ — between that of rocky and gaseous planets.
Is GJ 1252 b in the Habitable Zone?
The position of GJ 1252 b relative to the habitable zone of GJ 1252 cannot be precisely determined from the available orbital data.
Habitable zone of GJ 1252: 0.115–0.298 AU (conservative: 0.145–0.282 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 1252 b — one full orbit around GJ 1252 — lasts just 12.4 hours, shorter than Mercury's 88-day year.
How Was GJ 1252 b Discovered?
GJ 1252 b was discovered in 2020 using the transit method, with observations from Transiting Exoplanet Survey Satellite (TESS).
The transit method watches a star for the tiny, regular dip in brightness that occurs when a planet crosses in front of it. The depth and timing of these dips reveal the planet's size and orbital period.
How Far Away Is GJ 1252 b?
GJ 1252 b is 66.4 light-years (20.4 parsecs) from Earth. Light arriving here tonight left the planet around the year 1960. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 1,168,640 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 1252 b scores 0.30, ranking #1,505 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: GJ 1252
GJ 1252
- Spectral type
- M3
- Surface temperature
- 3,458 K (Sun: 5,772 K)
- Mass
- 0.38 M☉
- Radius
- 0.39 R☉
- Luminosity
- 0.0196 L☉
Planetary System
GJ 1252 b is the only planet known to orbit GJ 1252 so far.
GJ 1252 b — Complete Data
| Radius | 1.193 Earth radii (0.106 Jupiter radii) |
|---|---|
| Mass | 1.32 Earth masses (0.004 Jupiter masses) |
| Density | 4.20 g/cm³ (Earth: 5.51) |
| Orbital period | 0.52 days |
| Earth Similarity Index | 0.30 |
| Distance from Earth | 66.4 light-years (20.4 parsecs) |
| Constellation | Telescopium |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2020 |
Data: NASA Exoplanet Archive, last updated 2023-07-10. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About GJ 1252 b
Is GJ 1252 b habitable?
GJ 1252 b is not known to orbit within the habitable zone of GJ 1252, and as a terrestrial planet it is an unlikely candidate for life as we know it.
How far away is GJ 1252 b?
GJ 1252 b is about 66 light-years from Earth in the constellation Telescopium. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 1,168,640 years to get there.
How big is GJ 1252 b compared to Earth?
GJ 1252 b has 1.19 times the radius of Earth and about 1.3 times its mass.
How long is a year on GJ 1252 b?
One orbit around GJ 1252 takes 0.5 Earth days — short enough that 705 of its years would fit into one Earth year.
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