HD 55696 b
HD 55696 b is a cold gas giant orbiting the G0 V star HD 55696 in the constellation Puppis. It lies about 254 light-years from Earth and was discovered in 2018 using the radial velocity method.
Is HD 55696 b in the Habitable Zone?
HD 55696 b orbits beyond the outer edge of the habitable zone of HD 55696. At that distance, any surface water would almost certainly be frozen.
Habitable zone of HD 55696: 1.214–2.843 AU (conservative: 1.537–2.696 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 55696 b — one full orbit around HD 55696 — lasts 1,827.0 Earth days, longer than an Earth year. It orbits at an average distance of 3.180 AU. Its orbit is highly elliptical (eccentricity 0.71), swinging dramatically closer to and farther from its star.
How Was HD 55696 b Discovered?
HD 55696 b was discovered in 2018 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 55696 b?
HD 55696 b is 254.3 light-years (78.0 parsecs) from Earth. Light arriving here tonight left the planet around the year 1772. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 4,475,680 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 55696 b scores 0.31, ranking #1,090 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 55696
HD 55696
- Spectral type
- G0 V
- Surface temperature
- 6,012 K (Sun: 5,772 K)
- Mass
- 1.29 M☉
- Radius
- 1.52 R☉
- Luminosity
- 2.6915 L☉
- Age
- 2.6 billion years (Sun: 4.6)
Planetary System
HD 55696 b is the only planet known to orbit HD 55696 so far.
HD 55696 b — Complete Data
| Mass (best estimate) | 1,230.00 Earth masses |
|---|---|
| Orbital period | 1,827.00 days |
| Orbital distance | 3.180 AU |
| Eccentricity | 0.705 |
| Earth Similarity Index | 0.31 |
| Distance from Earth | 254.3 light-years (78.0 parsecs) |
| Constellation | Puppis |
| Discovery method | Radial Velocity |
| Discovery facility | W. M. Keck Observatory |
| Discovery year | 2018 |
Data: NASA Exoplanet Archive, last updated 2018-09-25. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 55696 b
Is HD 55696 b habitable?
No — HD 55696 b orbits outside the habitable zone of HD 55696 and is likely too cold for liquid water on its surface.
How far away is HD 55696 b?
HD 55696 b is about 254 light-years from Earth in the constellation Puppis. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 4,475,680 years to get there.
How long is a year on HD 55696 b?
One orbit around HD 55696 takes 1,827.0 Earth days.
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