Preon star

A preon star is a compact star made of preons, a group of subatomic particles that compose quarks and leptons. Preon stars would be expected to have huge densities, exceeding 1020 g/cm³ — intermediate between neutron stars and black holes. A preon star having the same mass as a standard planet would be about five meters in diameter.

Such objects could be detected in principle through gravitational lensing of gamma rays. The presence of preon stars could potentially explain the puzzling observations that lead to the dark matter hypothesis.

Preon stars could originate from supernova explosions or the big bang, although it seems difficult to explain how such light and compact objects could be formed.