Upsilon Andromedae b
Planet· orbits Upsilon Andromedae
Upsilon Andromedae b (Saffar) - a hot Jupiter (minimum mass ~0.7 Jupiter) skimming its star every 4.6 days. Found from the star's wobble, its mass is a minimum and it has never transited or been imaged.
Open in 3D viewSee Upsilon Andromedae b in the live, interactive 3D map
Key facts
Minimum mass
1.31 × 10²⁷ kg
0.688 M♃ (219 M⊕)
Year
4.62 Earth days
Distance from Upsilon Andromedae
8,856,194 km
Science
Physical
- Minimum mass (m·sin i)
- 1.31 × 10²⁷ kg · 0.688 M♃ (219 M⊕)
- Radial-velocity detection measures m·sin i; the true mass depends on the unknown orbital inclination.
- Radius
- Not measured
- No transit — radius is a model estimate for a hot Jupiter of at least ~0.7 Jupiter masses; true size unknown.
Orbital
- Semi-major axis
- 8,856,194 km
- From the NASA Exoplanet Archive (radial-velocity orbit)
- Eccentricity
- 0.022
- From the NASA Exoplanet Archive (radial-velocity orbit)
- Inclination
- 0.00 °
- From the NASA Exoplanet Archive (radial-velocity orbit)
- Orbital period
- 4.6 days
- From the NASA Exoplanet Archive (radial-velocity orbit)
- Perihelion
- 8,661,358 km
- Computed from the orbital elements
- Aphelion
- 9,051,030 km
- Computed from the orbital elements
- Mean orbital velocity
- 139 km/s
- Computed from the orbital elements
Composition
- Bulk composition
- A hot gas giant (minimum mass ~0.7 Jupiter) of hydrogen and helium; among the first hot Jupiters found (1996). 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
- 956 S⊕ · 956× the sunlight Earth receives
- Computed from Upsilon Andromedae's luminosity and the orbital distance (inverse-square; Earth's sunlight = 1).
- Equilibrium temperature
- 1,524 K (1,251 °C)
- Computed model value for its 4.6-day orbit — not measured.
Discovery & history
- Method
- Radial-velocity detection (stellar wobble)
- Name
- Designated 'b' 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').
Discovered in 1996, among the first hot Jupiters found - the innermost of what became the first multi-planet main-sequence system.
Images
No official imagery available — this object has never been visited and no officially-licensed depiction exists.