Confirmed exoplanet · Database record + computed analysis
YZ Cet c
A confirmed world orbiting YZ Cet, 12.1 light-years away.
An Earth-sized world
1.05 times Earth's radius, squarely in the terrestrial size range. With 1.1 Earth masses packed into that size, its density points to rock and iron rather than gas.
The orbit
Its year, one full orbit, takes just 3.1 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 137 °C. Above water's boiling point. It receives 4.7 times the starlight Earth gets.
Its sun
Its star is a red dwarf (3,151 K surface), type M4.5 V: small, dim, flare-prone, and destined to outlive the Sun many times over. It shares the system with 2 other known planets.
How far is that, really?
At 12 light-years, tonight's light from this system left it around the year 2013. That is close by galactic standards, which makes it a prime target for follow-up telescopes. A Voyager-speed probe would need roughly 214,207 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 2017 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.