Stellar Structure of Dark Stars: a First Phase of Stellar Evolution Resulting from Dark Matter Annihilation

Dark Stars are the very first phase of stellar evolution in the history of the universe: the first stars to form (at redshifts z ∼ 10 − 50) are powered by heating from dark matter (DM) annihilation instead of fusion (if the DM is made of particles which are their own antiparticles). We find equilibrium polytropic configurations for these stars; we start from the time DM heating becomes important (M ∼ 1 − 10 M⊙) and build up the star via accretion up to 1000 M⊙. The dark stars, with an assumed particle mass of 100 GeV, are found to have luminosities of a few times 10 L⊙, surface temperatures of 4000–10,000 K, radii ∼ 10 cm, lifetimes of ≈ 0.5 Myr, and are predicted to show lines of atomic and molecular hydrogen. Dark stars look quite different from standard metal-free stars without DM heating and can be distinguished in future observations, possibly even by JWST or TMT. Subject headings: Dark Matter