TOI-5734 b

TOI-5734 b
Artistic representation of exoplanet TOI-5734 b
Discovery
Discovered byS. Filomeno et al.
Discovery dateFebruary 20, 2026
Transit
Orbital characteristics
0.05921±0.00024 AU
6.1841876+0.0000080
−0.0000094
 d
Inclination89.88+0.12
−0.63
StarTOI-5734
Physical characteristics
2.10±0.12 R🜨
Mass9.10±2.60 M🜨
Mean density
0.98+0.36
−0.30
 ρ🜨
20.2+6.6
−6.0
 m/s2
Temperature688 ± 23 K (414.9 ± 23.0 °C; 778.7 ± 41.4 °F)
Atmosphere
Composition by volumeNone or extremely thin

TOI-5734 b is a confirmed exoplanet orbiting the young orange dwarf star TOI-5734, a K3-K4 spectral class star, at a distance of approximately 106 light-years from the Sun. The discovery of the object was officially announced by an international team of astronomers led by Simone Filomeno in late February 2026.

The planet is classified as a hot sub-Neptune with a density of 0.98 ρ🜨, a mass of 9.1 M🜨, and a radius of approximately 2.1 R🜨. The planet completes a full orbit around its star in approximately 6.18 Earth days at an average distance of about 0.06 AU. The equilibrium surface temperature is estimated to be 688 K, or about 415 °C. The object's density indicates a rocky composition. It is hypothesized that the planet has almost entirely lost its primordial hydrogen-helium atmosphere due to intense irradiation from its host star.

The parameters of TOI-5734 b place it at the upper boundary of the radius gap. This makes it a priority target for studying the transition from gaseous sub-Neptunes to rocky super-Earths.