Confirmed exoplanet · Database record + computed analysis
GJ 238 b
A confirmed world orbiting GJ 238, 49.6 light-years away.
A sub-Earth
smaller than Earth at 0.57 Earth radii. Worlds this small are hard to detect, so every one is a catch.
The orbit
Its year, one full orbit, takes just 1.7 Earth days. 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 485 °C. Hotter than Venus's surface. It receives 229.5 times the starlight Earth gets.
Its sun
Its star is a red dwarf (3,485 K surface), type M2.5 V: small, dim, flare-prone, and destined to outlive the Sun many times over.
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 877,943 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 2024 from Transiting Exoplanet Survey Satellite (TESS).
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.