Gliese 876 d
Planet· orbits Gliese 876
Gliese 876 d - the innermost planet, a hot super-Earth/mini-Neptune (~6.8 Earth masses) whipping around the star every 2 days. Its true mass is known from the system's dynamics, but it has never transited, so its size and appearance are model-based. Never imaged.
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Key facts
Mass
4.08 × 10²⁵ kg
6.83 M⊕
Year
1.94 Earth days
Distance from Gliese 876
3,111,636 km
Science
Physical
- Mass
- 4.08 × 10²⁵ kg · 6.83 M⊕
- Radius
- Not measured
- No transit — radius is a model estimate for a ~6.8-Earth-mass world; true size unknown.
Orbital
- Semi-major axis
- 3,111,636 km
- From the NASA Exoplanet Archive (radial-velocity orbit)
- Eccentricity
- 0.207
- From the NASA Exoplanet Archive (radial-velocity orbit)
- Inclination
- 0.00 °
- From the NASA Exoplanet Archive (radial-velocity orbit)
- Orbital period
- 46.51 hours
- From the NASA Exoplanet Archive (radial-velocity orbit)
- Perihelion
- 2,467,527 km
- Computed from the orbital elements
- Aphelion
- 3,755,744 km
- Computed from the orbital elements
- Mean orbital velocity
- 117 km/s
- Computed from the orbital elements
Composition
- Bulk composition
- A ~6.8-Earth-mass world of uncertain make-up (rocky or volatile-rich); its true mass is known from the system's dynamics, but it has never been imaged.
- Cloud appearance
- Appearance based on ESO/M. Kornmesser's artist's concept. No spacecraft has imaged this world, so its real appearance is unknown — The banded clouds shown are a representation of its class, shown only in Visual mode; Realism shows a plain spectral colour.
Radiation & temperature
- Insolation
- 28.7 S⊕ · 28.7× the sunlight Earth receives
- Computed from Gliese 876's luminosity and the orbital distance (inverse-square; Earth's sunlight = 1).
- Equilibrium temperature
- 603 K (330 °C)
- Computed model value (no atmosphere assumed) for its 2-day orbit — not measured.
Discovery & history
- Method
- Radial-velocity detection (stellar wobble)
- Name
- Designated 'd' under the IAU convention that letters a star's planets 'b', 'c', 'd'... in the order they are discovered (the star itself is the unwritten 'a').
Found by HARPS in 2005 as a then-record low-mass planet - the inner companion to the system's two giants.
Images
No official imagery available — this object has never been visited and no officially-licensed depiction exists.