BD+05 4868 A b
BD+05 4868 A b is a super-Earth orbiting the K V star BD+05 4868 A in the constellation Pegasus. It lies about 142 light-years from Earth and was discovered in 2025 using the transit method.
Is BD+05 4868 A b in the Habitable Zone?
BD+05 4868 A b orbits inside the inner edge of the habitable zone of BD+05 4868 A. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of BD+05 4868 A: 0.349–0.859 AU (conservative: 0.442–0.814 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 ›
Temperature on BD+05 4868 A b
The equilibrium temperature of BD+05 4868 A b is about 1,820 K (1,547 °C) — hot enough to melt many metals. This estimate ignores any atmosphere, which could change surface temperatures dramatically — Earth's greenhouse effect adds about 33 °C.
Orbit and Year Length
A year on BD+05 4868 A b — one full orbit around BD+05 4868 A — lasts just 30.5 hours, shorter than Mercury's 88-day year. It orbits at an average distance of 0.021 AU — closer to its star than Mercury is to the Sun.
How Was BD+05 4868 A b Discovered?
BD+05 4868 A b was discovered in 2025 using the transit method, with observations from Transiting Exoplanet Survey Satellite (TESS).
The transit method watches a star for the tiny, regular dip in brightness that occurs when a planet crosses in front of it. The depth and timing of these dips reveal the planet's size and orbital period.
How Far Away Is BD+05 4868 A b?
BD+05 4868 A b is 142.1 light-years (43.6 parsecs) from Earth. Light arriving here tonight left the planet around the year 1884. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 2,500,960 years to make the journey.
The Host Star: BD+05 4868 A
BD+05 4868 A b belongs to a system of 2 stars; it orbits BD+05 4868 A.
BD+05 4868 A
- Spectral type
- K V
- Surface temperature
- 4,596 K (Sun: 5,772 K)
- Mass
- 0.70 M☉
- Radius
- 0.69 R☉
- Luminosity
- 0.1920 L☉
- Age
- 11.1 billion years (Sun: 4.6)
Planetary System
BD+05 4868 A b is the only planet known to orbit BD+05 4868 A so far.
BD+05 4868 A b — Complete Data
| Mass | 6.20 Earth masses (0.020 Jupiter masses) |
|---|---|
| Orbital period | 1.27 days |
| Orbital distance | 0.021 AU |
| Equilibrium temperature | 1,820 K (1,547 °C) |
| Distance from Earth | 142.1 light-years (43.6 parsecs) |
| Constellation | Pegasus |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2025 |
Data: NASA Exoplanet Archive, last updated 2025-03-21. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About BD+05 4868 A b
Is BD+05 4868 A b habitable?
No — BD+05 4868 A b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is BD+05 4868 A b?
BD+05 4868 A b is about 142 light-years from Earth in the constellation Pegasus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 2,500,960 years to get there.
How long is a year on BD+05 4868 A b?
One orbit around BD+05 4868 A takes 1.3 Earth days — short enough that 287 of its years would fit into one Earth year.
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