13point8100 ly map
2 known planets · 11.6 light years

Gliese 15 A

Gliese 15 A is a red dwarf (M1) 11.6 light years away, with 2 confirmed planets. Distances and orbital speeds are to scale; the star and planets are enlarged so you can see them.

Day 0
habitable zone (estimate)planet orbits

Green band: where liquid water could exist on a planet's surface. Drag to turn the system, pinch or scroll to zoom.

The star

The star

Gliese 15 A

Type
M1
Surface
≈ 3,607 K
Size
0.38 × the Sun
Mass
0.38 × the Sun
Brightness
0.0221 × the Sun
Habitable zone
0.121–0.314 AU

The planets

Gliese 15 A

GJ 15 A b

Year
11.44 days
Distance from star
0.072 AU
Mass
at least 3 Earths
Size
1.6 × Earth
Temperature
≈ 550 K (+277 °C)
Found
2014, radial velocity (W. M. Keck Observatory)
Too hot
Gliese 15 A

GJ 15 A c

Year
20.8 years
Distance from star
5.4 AU
Mass
at least 36 Earths
Size
6.7 × Earth
Temperature
≈ 46 K (-227 °C)
Found
2018, radial velocity (Roque de los Muchachos Observatory)
Outside the habitable zone

Masses found by the wobble method are minimums, because the orbit's tilt is unknown. Temperatures are equilibrium estimates for a bare planet, before any atmosphere.

How we know

The wobble

The planet tugs its star back and forth. Spectrographs measure the tiny shift in the star's light, which gives the planet's year and a minimum mass.

Sources

  1. Planet and star parameters: NASA Exoplanet Archive, Planetary Systems Composite Parameters, retrieved 31 Oct 2026. This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with NASA under the Exoplanet Exploration Program.
  2. Position: HYG Database v4.1 (CC BY-SA 4.0).
  3. Habitable zone: a simple estimate from the star's brightness (√L × 0.95 to 1.67 AU), shown as a guide.
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