GJ 649 b
GJ 649 b is a cold gas giant orbiting the M1.0 star GJ 649 in the constellation Hercules. It lies about 34 light-years from Earth and was discovered in 2009 using the radial velocity method.
Is GJ 649 b in the Habitable Zone?
GJ 649 b orbits beyond the outer edge of the habitable zone of GJ 649. At that distance, any surface water would almost certainly be frozen.
Habitable zone of GJ 649: 0.170–0.436 AU (conservative: 0.215–0.414 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Orbit and Year Length
A year on GJ 649 b — one full orbit around GJ 649 — lasts 600.1 Earth days, longer than an Earth year. It orbits at an average distance of 1.112 AU. Its orbit is mildly elliptical (eccentricity 0.08).
How Was GJ 649 b Discovered?
GJ 649 b was discovered in 2009 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 GJ 649 b?
GJ 649 b is 33.9 light-years (10.4 parsecs) from Earth. Light arriving here tonight left the planet around the year 1993. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 596,640 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. GJ 649 b scores 0.12, ranking #4,341 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: GJ 649
GJ 649
- Spectral type
- M1.0
- Surface temperature
- 3,734 K (Sun: 5,772 K)
- Mass
- 0.51 M☉
- Radius
- 0.50 R☉
- Luminosity
- 0.0436 L☉
Planetary System
GJ 649 b is the only planet known to orbit GJ 649 so far.
GJ 649 b — Complete Data
| Mass (best estimate) | 82.00 Earth masses |
|---|---|
| Orbital period | 600.10 days |
| Orbital distance | 1.112 AU |
| Eccentricity | 0.083 |
| Earth Similarity Index | 0.12 |
| Distance from Earth | 33.9 light-years (10.4 parsecs) |
| Constellation | Hercules |
| Discovery method | Radial Velocity |
| Discovery facility | W. M. Keck Observatory |
| Discovery year | 2009 |
Data: NASA Exoplanet Archive, last updated 2023-07-10. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About GJ 649 b
Is GJ 649 b habitable?
No — GJ 649 b orbits outside the habitable zone of GJ 649 and is likely too cold for liquid water on its surface.
How far away is GJ 649 b?
GJ 649 b is about 34 light-years from Earth in the constellation Hercules. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 596,640 years to get there.
How long is a year on GJ 649 b?
One orbit around GJ 649 takes 600.1 Earth days.
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