About this world
TOI-2015 c is a sub-Neptune orbiting TOI-2015, a cool red dwarf (type M4+/-0.) 154 light-years from Earth. It is about 2.9 times the size of Earth (its size estimated from its mass) and holds 8.9 Earth masses. It completes an orbit every 5.58 days at 0.041 AU from its star, closer than Mercury is to the Sun.
Its equilibrium temperature is about 448 K (175 °C): far too hot for liquid water on its surface. At its size it almost certainly keeps a deep envelope of hydrogen and helium.
It was discovered in 2025 by timing variations with Multiple Observatories. Pulsar, eclipse or transit timings drift as an unseen companion tugs on them. TOI-2015 has 2 known planets; the others are TOI-2015 b.