HR 8799 c
Planet· orbits HR 8799
HR 8799 c — a young giant (~7-10 Jupiter masses) imaged at ~38 AU, on a ~190-year orbit. Water and methane have been detected in its glowing atmosphere by spectroscopy of the direct-image light. Size and mass are model estimates, so no density is quoted.
Open in 3D viewSee HR 8799 c in the live, interactive 3D map
Key facts
Mass
1.79 × 10²⁸ kg
9.44 M♃ (3,000 M⊕)
Year
189 Earth years
69,000 Earth days
Distance from HR 8799
38 AU
Science
Physical
- Mass
- 1.79 × 10²⁸ kg · 9.44 M♃ (3,000 M⊕)
- Radius
- Not measured
- Imaged, never transited: size and mass are model estimates, so no density is quoted.
Orbital
- Semi-major axis
- 38 AU
- From the NASA Exoplanet Archive (direct imaging + orbit fit)
- Eccentricity
- 0.05
- From the NASA Exoplanet Archive (direct imaging + orbit fit)
- Inclination
- 0.00 °
- From the NASA Exoplanet Archive (direct imaging + orbit fit)
- Orbital period
- 188.91 years
- From the NASA Exoplanet Archive (direct imaging + orbit fit)
- Perihelion
- 36.1 AU
- Computed from the orbital elements
- Aphelion
- 39.9 AU
- Computed from the orbital elements
- Mean orbital velocity
- 5.99 km/s
- Computed from the orbital elements
Composition
- Bulk composition
- A young giant (~7–10 Jupiter masses) at ~38 AU. Spectra of its direct-image light reveal water and methane — chemistry read from an actual photograph of the planet. Self-luminous; true appearance unresolved.
- Cloud appearance
- Appearance based on NASA/JPL-Caltech'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
- 0.00393 S⊕ · 1/254 of the sunlight Earth receives
- Computed from HR 8799's luminosity and the orbital distance (inverse-square; Earth's sunlight = 1).
Discovery & history
- Method
- Directly imaged
- Name
- Designated 'c' under the IAU planet-lettering convention; no IAU proper name has been assigned.
One of the three planets directly imaged around HR 8799 in 2008.
Images
Directly imaged only as a point of light beside HR 8799 — see the system view for the real Keck time-lapse and Hubble images that show all four planets. No telescope has resolved this planet's disk or surface.