Key parameters at a glance
- A radius of 14.00 Earth radii
- A mass of 226.98 Earth masses
- Surface gravity around 1.16 g
- An orbital period of 30.088 days
- Semi-major axis 0.1296 AU
- Distance from Earth 15.25 light-years
- Earth Similarity Index 0.281
- Travel time at Voyager 1 speed 268,905 years
- Almost certainly tidally locked to its host star given the close orbit
3 siblings around GJ 876
GJ 876 c shares its host star with 3 other confirmed planets. Side-by-side measurements below.
GJ 876 c Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#415of 1771
top 23.4%
This planet
14.00R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | GJ 876 c | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 14.00 | 11.21 |
| Mass (M⊕) | 1.00 | 226.98 | 317.83 |
| Density (g/cm³) | 5.51 | 0.46 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.16 | 2.53 |
| Insolation (S⊕) | 1.00 | — | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 226.985 M⊕ | Direct mass measurement (not derived). |
| Minimum mass (M sin i) | 241.500 M⊕ | Lower bound from radial-velocity fitting. |
| Computed mass | 281.742 M⊕ | Model-computed mass (e.g. from mass-radius relation). |
Star Catalogue Identifiers
HIP
HIP 113020
TIC
TIC 188580272
Gaia DR2
Gaia DR2 2603090003484152064
Gaia DR3
Gaia DR3 2603090003484152064
System
GJ 876
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 30.09 Earth days (8.2% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.1296 AU.
Extended Orbital Architecture
RV semi-amplitude (K)
88.340 m/s
Transit mid-time (BJD)
2,453,029.2980
Long. of periastron (ω)
48.76°
Angular separation (arcsec)
27.70000
Eq. Temperature
—
Insolation (S⊕)
—
Earth = 1.00
Earth Similarity (ESI)
0.281
0 = alien, 1 = Earth-identical
Insufficient insolation data. Close-orbiting tidally-locked around a cool host.
Discovery Paper
Primary reference
Marcy et al. 2001Instrument
Multiple Instruments
Publication
2001-07
Observation locale
Ground
Discovery cohort
Planets confirmed in 2000 at Multiple Observatories (5 shown).
Host System: GJ 876
Spectral Class
M-type red dwarf
Effective Temperature
3,294 K — cooler than the Sun (5,778 K)
Estimated Age
1.00 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.300 R☉
Stellar Mass
0.320 M☉
Metallicity [Fe/H]
0.21
Extended Stellar Properties
Surface gravity (log g)
4.872 dex
Stellar density
10.866 g/cm³
Systemic radial velocity
-1.60 km/s
Rotational v·sin i
0.16 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 13 bands
Astrometric Data
Parallax
213.867 mas
Total Proper Motion
1,171.101 mas/yr
PM Right Ascension
957.96 mas/yr
PM Declination
-673.64 mas/yr
Galactic Cartesian (pc)
x = 0.928 · y = -0.278 · z = -0.246
Equatorial (J2000)
RA 343.32397° · Dec -14.26660°
Galactic ℓ, b
52.003° · -59.635°
Ecliptic λ, β
339.168° · -6.631°
HTM-20 index
-1428809485
Observation Record
Photometric series
3
RV measurements
4
Stellar spectra
13
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