HD 142245 b
HD 142245 b is a cold gas giant orbiting HD 142245 in the constellation Serpens. It lies about 317 light-years from Earth and was discovered in 2011 using the radial velocity method. It orbits within the habitable zone of its star — the region where liquid water could exist on a planet's surface.
Is HD 142245 b in the Habitable Zone?
HD 142245 b orbits within the optimistic habitable zone of HD 142245 — the broader region where liquid water might be possible under favorable atmospheric conditions.
Habitable zone of HD 142245: 2.641–6.406 AU (conservative: 3.346–6.073 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Orbit and Year Length
A year on HD 142245 b — one full orbit around HD 142245 — lasts 1,299.0 Earth days, longer than an Earth year. It orbits at an average distance of 2.780 AU.
How Was HD 142245 b Discovered?
HD 142245 b was discovered in 2011 using the radial velocity method, with observations from W. M. Keck 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 HD 142245 b?
HD 142245 b is 317.1 light-years (97.2 parsecs) from Earth. Light arriving here tonight left the planet around the year 1709. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 5,580,960 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. HD 142245 b scores 0.36, ranking #676 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 142245
HD 142245 b belongs to a system of 3 stars; it orbits HD 142245.
HD 142245
- Surface temperature
- 4,922 K (Sun: 5,772 K)
- Mass
- 3.50 M☉
- Radius
- 4.63 R☉
Planetary System
HD 142245 b is the only planet known to orbit HD 142245 so far.
HD 142245 b — Complete Data
| Mass (best estimate) | 975.74 Earth masses |
|---|---|
| Orbital period | 1,299.00 days |
| Orbital distance | 2.780 AU |
| Earth Similarity Index | 0.36 |
| Distance from Earth | 317.1 light-years (97.2 parsecs) |
| Constellation | Serpens |
| Discovery method | Radial Velocity |
| Discovery facility | W. M. Keck Observatory |
| Discovery year | 2011 |
Data: NASA Exoplanet Archive, last updated 2018-09-04. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 142245 b
Is HD 142245 b habitable?
HD 142245 b orbits within the habitable zone of HD 142245, the region where liquid water could exist on a planet's surface. Whether it is actually habitable depends on its atmosphere and composition, which remain unknown.
How far away is HD 142245 b?
HD 142245 b is about 317 light-years from Earth in the constellation Serpens. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 5,580,960 years to get there.
How long is a year on HD 142245 b?
One orbit around HD 142245 takes 1,299.0 Earth days.
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