Confirmed exoplanet · Database record + computed analysis
GJ 317 c
A confirmed world orbiting GJ 317, 49.6 light-years away.
A gas giant
13.60 Earth radii, Jupiter-class (Jupiter is 11.2). At only 454.5 Earth masses for that size, it must be substantially gas or volatile ices: puffy, not rocky.
The orbit
Its year takes 6,500 Earth days (17.8 Earth years).
Temperature and starlight
Its equilibrium temperature (the airless-world estimate) is about -225 °C. Deep-freeze territory, colder than Antarctica's worst. It receives only 0.00 times Earth's starlight.
Its sun
Its star is a red dwarf (3,496 K surface), type M3.5 V: small, dim, flare-prone, and destined to outlive the Sun many times over. It shares the system with 1 other known planet.
How far is that, really?
At 50 light-years, tonight's light from this system left it around the year 1976. That is close by galactic standards, which makes it a prime target for follow-up telescopes. A Voyager-speed probe would need roughly 876,939 years to get there.
How we found it
It was found by the radial-velocity method: the planet's gravity swings its star in a small circle, and that wobble shows up as a rhythmic Doppler shift in the starlight. The wobble's size gives the planet's minimum mass. The discovery was announced in 2016 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.