Confirmed exoplanet · Database record + computed analysis
SPECULOOS-3 b
A confirmed world orbiting SPECULOOS-3.
An Earth-sized world
0.98 times Earth's radius, squarely in the terrestrial size range. With 0.9 Earth masses packed into that size, its density points to rock and iron rather than gas.
The orbit
Its year lasts about 17.3 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 280 °C. Above water's boiling point. It receives 15.5 times the starlight Earth gets.
Its sun
Its star is a red dwarf (2,800 K surface), type M6.5+/-0.5: small, dim, flare-prone, and destined to outlive the Sun many times over.
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 SPECULOOS Southern 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.