The star
The star
HAT-P-12
- Type
- K4
- Surface
- ≈ 4,650 K
- Size
- 0.70 × the Sun
- Mass
- 0.73 × the Sun
- Brightness
- 0.21 × the Sun
- Habitable zone
- 0.364–0.894 AU
The planets
HAT-P-12
HAT-P-12 b
- Year
- 3.21 days
- Distance from star
- 0.0384 AU
- Mass
- 67 Earths
- Size
- 11 × Earth
- Temperature
- ≈ 963 K (+690 °C)
- Found
- 2009, transit (HATNet)
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 1 Nov 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.