TOI-2015: A Nearby M-Dwarf with Two Known Worlds

TOI-2015 is an M4 +/- 0.5 spectral type star located 154 light-years away. Its spectral class places it among the small, cool red dwarfs. The star has a reported mass of 0.304 solar masses and a reported radius of 0.327 solar radii, both smaller than the Sun's. Its temperature is 3300 K, cooler than the Sun's, and its age carries a reported upper limit of 5.5 billion years. The system has one star, and two planets are known to orbit this host.

TOI-2015 b was discovered in 2023 by the transit method, which detects the small dip in a star's brightness when a planet passes in front of it. It is a Neptune-like planet, a size class reaching up to four times Earth's radius. Its reported radius is 3.31 Earth radii, larger than Earth's, and its reported mass is 9.2 Earth masses, also larger than Earth's. Its mean density is 1.4 g/cm³, 0.254 times Earth's. TOI-2015 b completes an orbit in 3.35 days, the shortest year among the listed planets.

TOI-2015 c was discovered in 2025 using transit timing variations. Its reported mass is 8.91 Earth masses, larger than Earth's, and it orbits in 5.58 days, the longest year among the listed planets. Among the listed planets, TOI-2015 b has the largest reported mass at 9.2 Earth masses, while TOI-2015 c has the smallest at 8.91 Earth masses.