Confirmed exoplanet · Database record + computed analysis
HR 8799 d
A confirmed world orbiting HR 8799, 134.5 light-years away.
A gas giant
13.00 Earth radii, Jupiter-class (Jupiter is 11.2). With 3000.0 Earth masses packed into that size, its density points to rock and iron rather than gas.
The orbit
Its year takes 37,000 Earth days (101.3 Earth years). The orbit is strongly stretched (eccentricity 0.60), so its distance from the star, and with it the climate, swings dramatically.
Temperature and starlight
Its equilibrium temperature (the airless-world estimate) is about 1,027 °C. Hot enough to melt copper; any surface would glow. It receives only 0.01 times Earth's starlight.
Its sun
Its star is hotter than the Sun (7,205 K, A5 V), burning brighter and faster. It shares the system with 3 other known planets.
How far is that, really?
At 135 light-years, tonight's light from this system left it around the year 1891. A Voyager-speed probe would need roughly 2,380,012 years to get there.
How we found it
It was directly imaged, one of the rare planets actually photographed as its own point of light, possible only for young, hot, wide-orbiting giants. The discovery was announced in 2008 from W. M. Keck Observatory.
Everything above is computed from the archive’s measured values for this planet. Where a quantity is missing, the statement is omitted rather than guessed.
About this record
The measured values come from the NASA Exoplanet Archive, and any missing value has not been determined yet; the Atlas never fills gaps with guesses. More standout worlds: Proxima b, TRAPPIST-1e, K2-18 b, 55 Cancri e, and the detection methods that found them all.