Confirmed exoplanet · Database record + computed analysis
K2-137 b
A confirmed world orbiting K2-137, 322.5 light-years away.
A sub-Earth
smaller than Earth at 0.64 Earth radii. Worlds this small are hard to detect, so every one is a catch. With 158.9 Earth masses packed into that size, its density points to rock and iron rather than gas.
The orbit
Its year lasts about 4.3 hours, making it an ultra-short-period planet skimming its star. Orbiting this tightly around a cool star, it is very likely tidally locked: one hemisphere in permanent day, the other in permanent night.
Temperature and starlight
Its equilibrium temperature (the airless-world estimate) is about 1,198 °C. Hot enough to melt copper; any surface would glow. It receives 975.6 times the starlight Earth gets.
Its sun
Its star is a red dwarf (3,697 K surface), type M3 V: small, dim, flare-prone, and destined to outlive the Sun many times over.
How far is that, really?
At 322 light-years, tonight's light from this system left it around the year 1703. A Voyager-speed probe would need roughly 5,705,720 years to get there.
How we found it
It was found by the transit method: the planet crosses its star's face on schedule, dimming it by a tiny, repeating fraction. The dip's depth gives the planet's size. The discovery was announced in 2017 from K2.
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.