Title: Supermassive Dark Stars and their detectability

Abstract: We propose two mechanisms that could explain the growth of Dark Stars to become supermassive (SMDS) of one to ten million solar masses. The growth continues as long as dark matter heating persists, since dark stars are large and cool and do not emit enough ionizing photons to prevent further accretion of baryons onto the star. The dark matter may be provided by two mechanisms: (1) gravitational attraction of dark matter particles on a variety of orbits not previously considered, and (2) capture of WIMPs due to elastic scattering. Once the dark matter fuel is exhausted, the SMDS becomes a heavy main sequence star. These stars eventually collapse to form massive black holes that may provide seeds for supermassive black holes in the Universe. The launch of the JWST opens up the possibility of detecting Dark Stars. Using various dropout redshift selection functions we show that JWST could detect SMDS in a typical deep field survey. We also discuss the possibility to differentiate SMDS from PopIII galaxies using photometry or spectroscopy.