eps CrB b
eps CrB b is a cold gas giant orbiting the K2 III star eps CrB in the constellation Corona Borealis. It lies about 228 light-years from Earth and was discovered in 2012 using the radial velocity method.
Is eps CrB b in the Habitable Zone?
eps CrB b orbits inside the inner edge of the habitable zone of eps CrB. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of eps CrB: 9.796–24.309 AU (conservative: 12.408–23.047 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 eps CrB b — one full orbit around eps CrB — lasts 417.9 Earth days, longer than an Earth year. It orbits at an average distance of 1.300 AU. Its orbit is mildly elliptical (eccentricity 0.11).
How Was eps CrB b Discovered?
eps CrB b was discovered in 2012 using the radial velocity method, with observations from Bohyunsan Optical Astronomical 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 eps CrB b?
eps CrB b is 227.9 light-years (69.9 parsecs) from Earth. Light arriving here tonight left the planet around the year 1799. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 4,011,040 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. eps CrB b scores 0.08, ranking #4,655 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: eps CrB
eps CrB
- Spectral type
- K2 III
- Surface temperature
- 4,406 K (Sun: 5,772 K)
- Mass
- 1.70 M☉
- Radius
- 21.00 R☉
- Age
- 1.7 billion years (Sun: 4.6)
Planetary System
eps CrB b is the only planet known to orbit eps CrB so far.
eps CrB b — Complete Data
| Mass (best estimate) | 2,129.46 Earth masses |
|---|---|
| Orbital period | 417.90 days |
| Orbital distance | 1.300 AU |
| Eccentricity | 0.110 |
| Earth Similarity Index | 0.08 |
| Distance from Earth | 227.9 light-years (69.9 parsecs) |
| Constellation | Corona Borealis |
| Discovery method | Radial Velocity |
| Discovery facility | Bohyunsan Optical Astronomical Observatory |
| Discovery year | 2012 |
Data: NASA Exoplanet Archive, last updated 2015-09-08. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About eps CrB b
Is eps CrB b habitable?
No — eps CrB b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is eps CrB b?
eps CrB b is about 228 light-years from Earth in the constellation Corona Borealis. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 4,011,040 years to get there.
How long is a year on eps CrB b?
One orbit around eps CrB takes 417.9 Earth days.
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