Gas-depleted planet formation occurred in the four-planet system around the red dwarf LHS 1903
- Thomas G. Wilson
- Anna M. Simpson
- Andrew Collier Cameron
- Ryan Cloutier
- Vardan Adibekyan
- Ancy Anna John
- Yann Alibert
- Manu Stalport
- Jo Ann Egger
- Andrea Bonfanti
- Nicolas Billot
- Pascal Guterman
- Pierre F. L. Maxted
- Attila E. Simon
- Sérgio G. Sousa
- Malcolm Fridlund
- Mathias Beck
- Anja Bekkelien
- Sébastien Salmon
- Valérie Van Grootel
- Luca Fossati
- Alexander James Mustill
- Hugh P. Osborn
- Tiziano Zingales
- Matthew J. Hooton
- Laura Affer
- Suzanne Aigrain
- Roi Alonso
- Guillem Anglada
- Alexandros Antoniadis-Karnavas
- Tamas Bárczy
- David Barrado Navascues
- Susana C. C. Barros
- Wolfgang Baumjohann
- Thomas Beck
- Willy Benz
- Federico Biondi
- Xavier Bonfils
- Luca Borsato
- Alexis Brandeker
- Christopher Broeg
- Lars A. Buchhave
- Maximilian Buder
- Juan Cabrera
- Sebastian Carrazco Gaxiola
- David Charbonneau
- Sébastien Charnoz
- David R. Ciardi
- Karen A. Collins
- Kevin I. Collins
2026-02-12
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.