Gas-depleted planet formation occurred in the four-planet system around the red dwarf LHS 1903
Summary
The radii of small exoplanets form two populations, super-Earths and sub-Neptunes, separated by a gap known as the radius valley. This feature could be produced by the removal of atmospheres by stellar or internal heating or by the lack of an initial envelope. We used transit photometry and radial velocity measurements to detect and characterize four exoplanets orbiting LHS 1903, a red dwarf star in the Milky Way's thick disk. These four planets have orbital periods ranging from 2.2 to 29.
Content
# Gas-depleted planet formation occurred in the four-planet system around the red dwarf LHS 1903
*Published: 2026 Apr 16*
The radii of small exoplanets form two populations, super-Earths and
sub-Neptunes, separated by a gap known as the radius valley. This feature could
be produced by the removal of atmospheres by stellar or internal heating or by
the lack of an initial envelope. We used transit photometry and radial velocity
measurements to detect and characterize four exoplanets orbiting LHS 1903, a red
dwarf star in the Milky Way's thick disk. These four planets have orbital
periods ranging from 2.2 to 29.3 days and span the radius valley within a single
planetary system. The derived densities indicate that LHS 1903 b is rocky,
whereas LHS 1903 c and LHS 1903 d have extended atmospheres. The most distant
planet from the host star, LHS 1903 e, has no gaseous envelope, indicating that
it formed from gas-depleted material.
DOI: 10.1126/science.adl2348