Confirmed exoplanet · Database record + computed analysis
HD 20781 e
A confirmed world orbiting HD 20781, 117.3 light-years away.
A sub-Neptune
3.83 Earth radii, likely a rocky core under a thick gas or steam envelope rather than a walkable surface. At only 14.0 Earth masses for that size, it must be substantially gas or volatile ices: puffy, not rocky.
The orbit
Its year, one full orbit, takes just 85.5 Earth days.
Temperature and starlight
Its equilibrium temperature (the airless-world estimate) is about 125 °C. Above water's boiling point. It receives 4.3 times the starlight Earth gets.
Its sun
Its star is an orange K-type (5,256 K), K0 V: cooler and longer-lived than the Sun, a class some astronomers consider ideal for habitability. The system holds 2 stars, so its skies have more than one sun. It shares the system with 4 other known planets.
How far is that, really?
At 117 light-years, tonight's light from this system left it around the year 1908. A Voyager-speed probe would need roughly 2,075,754 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 2019 from La Silla 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.