GJ 849 b
GJ 849 b is a cold gas giant orbiting the M3.5 star GJ 849 in the constellation Aquarius. It lies about 29 light-years from Earth and was discovered in 2006 using the radial velocity method.
Is GJ 849 b in the Habitable Zone?
GJ 849 b orbits beyond the outer edge of the habitable zone of GJ 849. At that distance, any surface water would almost certainly be frozen.
Habitable zone of GJ 849: 0.131–0.341 AU (conservative: 0.166–0.323 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 849 b — one full orbit around GJ 849 — lasts 1,925.3 Earth days, longer than an Earth year. It orbits at an average distance of 2.320 AU. Its orbit is nearly circular (eccentricity 0.029).
How Was GJ 849 b Discovered?
GJ 849 b was discovered in 2006 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 849 b?
GJ 849 b is 28.7 light-years (8.8 parsecs) from Earth. Light arriving here tonight left the planet around the year 1998. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 505,120 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 849 b scores 0.07, ranking #4,949 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: GJ 849
GJ 849
- Spectral type
- M3.5
- Surface temperature
- 3,467 K (Sun: 5,772 K)
- Mass
- 0.45 M☉
- Radius
- 0.45 R☉
- Luminosity
- 0.0257 L☉
The GJ 849 Planetary System
GJ 849 b is one of 2 known planets in the GJ 849 system. Its siblings:
- GJ 849 c (Cold Gas Giant)
GJ 849 b — Complete Data
| Mass (best estimate) | 283.82 Earth masses |
|---|---|
| Orbital period | 1,925.31 days |
| Orbital distance | 2.320 AU |
| Eccentricity | 0.029 |
| Earth Similarity Index | 0.07 |
| Distance from Earth | 28.7 light-years (8.8 parsecs) |
| Constellation | Aquarius |
| Discovery method | Radial Velocity |
| Discovery facility | W. M. Keck Observatory |
| Discovery year | 2006 |
Data: NASA Exoplanet Archive, last updated 2023-07-10. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About GJ 849 b
Is GJ 849 b habitable?
No — GJ 849 b orbits outside the habitable zone of GJ 849 and is likely too cold for liquid water on its surface.
How far away is GJ 849 b?
GJ 849 b is about 29 light-years from Earth in the constellation Aquarius. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 505,120 years to get there.
How long is a year on GJ 849 b?
One orbit around GJ 849 takes 1,925.3 Earth days.
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