Confirmed exoplanet · Database record + computed analysis
HD 137388 b
A confirmed world orbiting HD 137388, 132.0 light-years away.
A gas giant
9.32 Earth radii, Jupiter-class (Jupiter is 11.2). At only 63.6 Earth masses for that size, it must be substantially gas or volatile ices: puffy, not rocky.
The orbit
Its year takes 330 Earth days (0.9 Earth years). The orbit is strongly stretched (eccentricity 0.36), 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 -25 °C. In the range where, with the right atmosphere, liquid water is conceivable; a real atmosphere could shift the true surface figure a lot (Earth's equilibrium value is −18 °C, yet we average +15 °C). It receives 0.58 times Earth's starlight, the same order as our own world.
Its sun
Its star is an orange K-type (5,181 K), K2 IV: cooler and longer-lived than the Sun, a class some astronomers consider ideal for habitability.
How far is that, really?
At 132 light-years, tonight's light from this system left it around the year 1893. A Voyager-speed probe would need roughly 2,336,156 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 2011 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.