13point8100 ly map
2 known planets · 53.2 light years

GJ 143

GJ 143 is a orange dwarf (K4.5) 53.2 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

GJ 143

Type
K4.5
Surface
≈ 4,640 K
Size
0.69 × the Sun
Mass
0.73 × the Sun
Brightness
0.206 × the Sun
Habitable zone
0.431–0.758 AU

The planets

GJ 143

HD 21749 c

Year
7.79 days
Distance from star
0.0695 AU
Mass
3.7 Earths
Size
0.89 × Earth
Temperature
≈ 701 K (+428 °C)
Found
2019, transit (Transiting Exoplanet Survey Satellite (TESS))
Too hot
GJ 143

GJ 143 b

Year
35.61 days
Distance from star
0.192 AU
Mass
23 Earths
Size
2.6 × Earth
Temperature
≈ 422 K (+149 °C)
Found
2019, transit (Transiting Exoplanet Survey Satellite (TESS))
Too hot

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 shadow

The planet passes in front of its star and dims it by a fraction of a percent, every orbit. The dip gives the planet's size and year.

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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