The star
The star
ROXs 12
- Type
- M0
- Surface
- ≈ 3,850 K
- Size
- 1.07 × the Sun
- Mass
- 0.87 × the Sun
- Brightness
- 0.162 × the Sun
- Habitable zone
- 0.328–0.835 AU
The planets
ROXs 12
ROXs 12 b
- Year
- 3262.6 years
- Distance from star
- 210 AU
- Mass
- 16 Jupiters
- Size
- 12 × Earth
- Temperature
- ≈ 13 K (-260 °C)
- Found
- 2013, imaging (W. M. Keck Observatory)
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
A direct picture
The star's glare is blocked or subtracted, leaving the planet's own faint light as a dot that moves along its orbit over the years.
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.