HD 209458 b
A confirmed exoplanet orbiting HD 209458.
Compared with Earth
- Size
- About 16 times Earth's width.
- Mass
- About 232 times Earth's mass.
- Year
- A year here lasts about 3.5 Earth days.
Planet
- Radius
- 15.58 × Earth
- Mass
- 232 × Earth
- Density
- Unknown
- Equilibrium temperature
- Unknown
- Starlight received
- Unknown
- Orbital period
- 3.525 days
- Average distance from its star
- Unknown
Star
- Host star
- HD 209458
- Spectral class
- F — yellow-white
- Surface temperature
- 6,091 K
- Radius
- 1.19 × Sun
- Mass
- 1.23 × Sun
- Age
- Unknown
System
- Distance from Earth
- 157.5 light-years (48.3 parsecs)
- Stars in system
- 1
- Known planets
- 1
Discovery
- Year
- 1999
- Method
- Radial Velocity
- Facility
- W. M. Keck Observatory
Data from the NASA Exoplanet Archive, synced October 14, 2026.