BD+20 2457 c
BD+20 2457 c is a cold gas giant orbiting the K2 II star BD+20 2457 in the constellation Leo. It lies about 5,022 light-years from Earth and was discovered in 2009 using the radial velocity method.
Is BD+20 2457 c in the Habitable Zone?
BD+20 2457 c orbits inside the inner edge of the habitable zone of BD+20 2457. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of BD+20 2457: 31.093–78.167 AU (conservative: 39.384–74.109 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
See the full interactive habitable-zone view in the Exoplanet Explorer app ›
Orbit and Year Length
A year on BD+20 2457 c — one full orbit around BD+20 2457 — lasts 622.0 Earth days, longer than an Earth year. It orbits at an average distance of 2.010 AU. Its orbit is mildly elliptical (eccentricity 0.18).
How Was BD+20 2457 c Discovered?
BD+20 2457 c was discovered in 2009 using the radial velocity method, with observations from McDonald Observatory.
The radial velocity method measures the subtle wobble of a star caused by the gravitational pull of an orbiting planet, visible as periodic shifts in the star's light spectrum. The size of the wobble reveals the planet's minimum mass.
How Far Away Is BD+20 2457 c?
BD+20 2457 c is 5,021.9 light-years (1,539.7 parsecs) from Earth. Light arriving here tonight left the planet about 5,022 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 88,385,440 years to make the journey.
Earth Similarity Index
The Earth Similarity Index (ESI) scores how physically similar a planet is to Earth, from 0 to 1, based on radius, density, escape velocity and surface temperature. BD+20 2457 c scores 0.07, ranking #4,808 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: BD+20 2457
BD+20 2457
- Spectral type
- K2 II
- Surface temperature
- 4,137 K (Sun: 5,772 K)
- Mass
- 2.80 M☉
- Radius
- 49.00 R☉
- Luminosity
- 1,479.1084 L☉
The BD+20 2457 Planetary System
BD+20 2457 c is one of 2 known planets in the BD+20 2457 system. Its siblings:
BD+20 2457 c — Complete Data
| Mass (best estimate) | 3,963.17 Earth masses |
|---|---|
| Orbital period | 621.99 days |
| Orbital distance | 2.010 AU |
| Eccentricity | 0.180 |
| Earth Similarity Index | 0.07 |
| Distance from Earth | 5,021.9 light-years (1,539.7 parsecs) |
| Constellation | Leo |
| Discovery method | Radial Velocity |
| Discovery facility | McDonald Observatory |
| Discovery year | 2009 |
Data: NASA Exoplanet Archive, last updated 2014-05-14. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About BD+20 2457 c
Is BD+20 2457 c habitable?
No — BD+20 2457 c orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is BD+20 2457 c?
BD+20 2457 c is about 5,022 light-years from Earth in the constellation Leo. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 88,385,440 years to get there.
How long is a year on BD+20 2457 c?
One orbit around BD+20 2457 takes 622.0 Earth days.
Explore BD+20 2457 c in the app
Browse, filter and compare 6,000+ exoplanets on iPhone, iPad and Apple Watch — with habitable-zone views, widgets and offline data.
