TOI-4336 A b

A sub-Neptune

2.14 Earth radii, likely a rocky core under a thick gas or steam envelope rather than a walkable surface. At only 3.3 Earth masses for that size, it must be substantially gas or volatile ices: puffy, not rocky.

The orbit

Its year, one full orbit, takes just 16.3 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 36 °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 1.53 times Earth's starlight, the same order as our own world.

Its sun

Its star is a red dwarf (3,307 K surface), type M3.5 V: small, dim, flare-prone, and destined to outlive the Sun many times over. The system holds 3 stars, so its skies have more than one sun. It shares the system with 1 other known planet.

How far is that, really?

At 74 light-years, tonight's light from this system left it around the year 1952. A Voyager-speed probe would need roughly 1,301,000 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).

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.

Sister planets around TOI-4336 A