Upsilon Andromedae c
Planet· orbits Upsilon Andromedae
Upsilon Andromedae c (Samh) - a massive giant (~14 Jupiter masses) on an eccentric 241-day orbit. Astrometry gives its true mass; it has never transited, so its size is model-based. Never imaged.
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Key facts
Mass
2.65 × 10²⁸ kg
14 M♃ (4,443 M⊕)
Year
241 Earth days
Distance from Upsilon Andromedae
0.828 AU
Science
Physical
- Mass
- 2.65 × 10²⁸ kg · 14 M♃ (4,443 M⊕)
- Radius
- Not measured
- No transit — radius is a model estimate for a very massive giant; no density is quoted.
Orbital
- Semi-major axis
- 0.828 AU
- From the NASA Exoplanet Archive (radial-velocity orbit)
- Eccentricity
- 0.26
- From the NASA Exoplanet Archive (radial-velocity orbit)
- Inclination
- 0.00 °
- From the NASA Exoplanet Archive (radial-velocity orbit)
- Orbital period
- 241.2 days
- From the NASA Exoplanet Archive (radial-velocity orbit)
- Perihelion
- 0.613 AU
- Computed from the orbital elements
- Aphelion
- 1.04 AU
- Computed from the orbital elements
- Mean orbital velocity
- 37.3 km/s
- Computed from the orbital elements
Composition
- Bulk composition
- A massive gas giant of true (astrometric) mass ~14 Jupiter — hydrogen and helium; never 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
- 4.89 S⊕ · 4.89× the sunlight Earth receives
- Computed from Upsilon Andromedae's luminosity and the orbital distance (inverse-square; Earth's sunlight = 1).
- Equilibrium temperature
- 408 K (135 °C)
- Computed model value for its eccentric 241-day orbit — not measured.
Discovery & history
- Discovered
- April 15, 1999
- Method
- Radial-velocity detection (stellar wobble)
- Name
- Designated 'c' 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').
Announced in 1999 with planet d, making this the first multi-planet system found around a normal star.
Images
No official imagery available — this object has never been visited and no officially-licensed depiction exists.