The star
The star
LP 791-18
- Type
- M(6.1 +/- 0.7) V
- Surface
- ≈ 2,960 K
- Size
- 0.18 × the Sun
- Mass
- 0.14 × the Sun
- Brightness
- 0.0023 × the Sun
- Habitable zone
- 0.0394–0.105 AU
The planets
LP 791-18
LP 791-18 b
- Year
- 0.95 days
- Distance from star
- 0.00978 AU
- Mass
- 1.9 Earths
- Size
- 1.2 × Earth
- Temperature
- ≈ 564 K (+291 °C)
- Found
- 2019, transit (Transiting Exoplanet Survey Satellite (TESS))
LP 791-18
LP 791-18 d
- Year
- 2.75 days
- Distance from star
- 0.0199 AU
- Mass
- 0.91 Earths
- Size
- 1 × Earth
- Temperature
- ≈ 396 K (+122 °C)
- Found
- 2023, transit (Spitzer Space Telescope)
LP 791-18
LP 791-18 c
- Year
- 4.99 days
- Distance from star
- 0.0296 AU
- Mass
- 7.2 Earths
- Size
- 2.5 × Earth
- Temperature
- ≈ 324 K (+51 °C)
- Found
- 2019, transit (Transiting Exoplanet Survey Satellite (TESS))
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
- 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.
- Position: HYG Database v4.1 (CC BY-SA 4.0).
- Habitable zone: a simple estimate from the star's brightness (√L × 0.95 to 1.67 AU), shown as a guide.