TOI-836: A Nearby K-Dwarf with Two Transiting Planets

TOI-836 is a K V star located 89.7 light-years from Earth. Its spectral type, K V, identifies it as a main-sequence dwarf of the cooler K class. The star is 5.4 billion years old, and its reported mass of 0.678 solar masses, radius of 0.665 solar radii, and temperature of 4550 K are each smaller or cooler than the Sun’s corresponding values. Two planets are known to orbit this host.

Both planets were detected by the transit method. TOI-836 b, discovered in 2023, is classified as a Super-Earth. Its radius of 1.7 Earth radii is larger than Earth’s, and its mass of 4.53 Earth masses is likewise larger. Its mean density of 5.04 g/cm³ is 0.916 times Earth's. TOI-836 b completes an orbit in 3.82 days.

TOI-836.01, discovered in 2021, is a Neptune-like planet. Its radius of 2.59 Earth radii exceeds Earth’s, as does its mass of 9.6 Earth masses. Its mean density is 3.06 g/cm³, or 0.554 times Earth's. It orbits its star every 8.6 days.

Within this pair, TOI-836 b has the shorter year, the smaller radius, and the smaller reported mass. TOI-836.01 has the longer year, the larger radius, and the larger reported mass. It also carries the greater mean density of the two, completing its tighter orbit in 8.6 days.