The star
The star
XO-3
- Type
- F5V
- Surface
- ≈ 6,970 K
- Size
- 1.52 × the Sun
- Mass
- 1.45 × the Sun
- Brightness
- 4.92 × the Sun
- Habitable zone
- 1.55–3.59 AU
The planets
XO-3
XO-3 b
- Year
- 3.19 days
- Distance from star
- 0.0481 AU
- Mass
- 13 Jupiters
- Size
- 15 × Earth
- Temperature
- ≈ 1890 K (+1617 °C)
- Found
- 2007, transit (XO)
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.