A Planetary System That Formed Backwards
The LHS 1903 system defies planetary formation theory. Four planets orbit this red dwarf 116 light-years away, arranged rocky → gaseous → gaseous → rocky. The outermost world is a small super-Earth, not a gas giant. Standard theory says rocky planets form close to stars (where heat vaporizes gases) while gas giants form in cold outer reaches. LHS 1903e broke this rule — likely forming late, after the primordial gas disk had dissipated. A planet born from rock alone.
Wilson et al., Science, February 2026 — CHEOPS/TESS
Click: cycle view | R: radius valley | C: comparison | Space: pause | I: info