HR 8799 e
Planet· orbits the Sun
HR 8799 e — the innermost of the four imaged giants (~7-10 Jupiter masses), orbiting at ~16 AU over roughly 57 years. Young and hot (~1,150 K), it still glows with its own heat — which is how it can be photographed. Its size and mass are model estimates from that glow, so no density is quoted.
Open in 3D viewSee HR 8799 e in the live, interactive 3D map
Key facts
Mass
1.90 × 10²⁸ kg
10 M♃ (3,178 M⊕)
Year
57 Earth years
20,816 Earth days
Distance from HR 8799
16.4 AU
Science
Physical
- Mass
- 1.90 × 10²⁸ kg · 10 M♃ (3,178 M⊕)
- Radius
- Not measured
Orbital
- Semi-major axis
- 16.4 AU
- Eccentricity
- 0.15
- Inclination
- 0.00 °
- Orbital period
- 56.99 years
- Perihelion
- 13.9 AU
- Aphelion
- 18.9 AU
- Mean orbital velocity
- 8.57 km/s
Composition
- Bulk composition
- A young gas giant of roughly 7–10 Jupiter masses at ~16 AU, still glowing at ~1,150 K from the heat of its own formation — which is how it can be photographed beside its star. Hydrogen/helium; 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 Vision mode; Realism shows a plain spectral colour.
Radiation & temperature
- Insolation
- 0.0211 S⊕ · 2% of the sunlight Earth receives
Discovery & history
- Method
- Directly imaged
- Name
- Designated 'e' under the IAU planet-lettering convention; no IAU proper name has been assigned.
Directly imaged in 2010, completing the quartet — the closest-in and hardest to separate from the star's glare.
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.