BD+48 738 b
BD+48 738 b is a cold gas giant orbiting the K0 III star BD+48 738 in the constellation Perseus. It lies about 2,842 light-years from Earth and was discovered in 2011 using the radial velocity method.
Is BD+48 738 b in the Habitable Zone?
BD+48 738 b orbits inside the inner edge of the habitable zone of BD+48 738. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of BD+48 738: 5.613–13.923 AU (conservative: 7.110–13.200 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+48 738 b — one full orbit around BD+48 738 — lasts 392.6 Earth days, longer than an Earth year. It orbits at an average distance of 1.000 AU — comparable to the inner Solar System. Its orbit is mildly elliptical (eccentricity 0.20).
How Was BD+48 738 b Discovered?
BD+48 738 b was discovered in 2011 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+48 738 b?
BD+48 738 b is 2,842.4 light-years (871.5 parsecs) from Earth. Light arriving here tonight left the planet about 2,842 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 50,026,240 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+48 738 b scores 0.09, ranking #4,563 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: BD+48 738
BD+48 738
- Spectral type
- K0 III
- Surface temperature
- 4,414 K (Sun: 5,772 K)
- Mass
- 0.74 M☉
- Radius
- 11.00 R☉
- Luminosity
- 48.9779 L☉
Planetary System
BD+48 738 b is the only planet known to orbit BD+48 738 so far.
BD+48 738 b — Complete Data
| Mass (best estimate) | 289.23 Earth masses |
|---|---|
| Orbital period | 392.60 days |
| Orbital distance | 1.000 AU |
| Eccentricity | 0.200 |
| Earth Similarity Index | 0.09 |
| Distance from Earth | 2,842.4 light-years (871.5 parsecs) |
| Constellation | Perseus |
| Discovery method | Radial Velocity |
| Discovery facility | McDonald Observatory |
| Discovery year | 2011 |
Data: NASA Exoplanet Archive, last updated 2015-08-12. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About BD+48 738 b
Is BD+48 738 b habitable?
No — BD+48 738 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is BD+48 738 b?
BD+48 738 b is about 2,842 light-years from Earth in the constellation Perseus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 50,026,240 years to get there.
How long is a year on BD+48 738 b?
One orbit around BD+48 738 takes 392.6 Earth days.
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