Dark stars are celestial objects heated by dark matter annihilation instead of nuclear fusion. In the preprint arXiv:2304.01173 three objects observed by JWST were identified as potential dark stars. However, these objects lacked high-resolution spectra required to distinguish them from early galaxies. Similar to conventional stars, dark stars are expected to display absorption lines, while galaxies often exhibit emission lines from nebulae within them. If these objects are observed to feature Helium-II absorption characteristics, it would provide strong evidence supporting their classification as dark stars rather than early galaxies.
This market will resolve as 'YES' if any of the three objects identified in 'arXiv:2304.01173' as dark star candidates are confirmed to exhibit Helium-II absorption spectra.
This market will resolve as 'NO' otherwise
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@JonathanRay There are a few things going on. One is that neutralinos cool off as the universe expands. They don’t need to couple to photons to do this. See the attached note.
There is more to this story however. Cold dark matter does not, by itself, form dense collapsed objects. Baryons can because they can radiate away energy. However as baryons collapse they deepen the gravity well felt by dark matter and this transfers energy from the dark matter to the baryons. This feedback can create much larger dark matter densities than dark matter only halos can and these are what could lead to dark stars.
It's easiest to understand why this happens by imagining a spherical shell of baryons contracting and imagining a dark matter particle falling in to it. As the dark matted falls into the gravity well of the baryons it picks up speed until crosses the edge of the shell. Inside of the shell the dark matter particle maintains the same velocity until it leaves the shell. But because the shell is contracting, the dark matter particle leaves deeper in the gravity well than is entered, so has lost energy.
This argument shows spherically symmetric collapsing objects “cool” the dark matter. The non spherically symmetric case is more complicated but is largely similar.
@JonathanRay Spectra have been taken but not with sufficient signal to noise to resolve the spectral lines.
@TomBouley They are very faint objects so it takes time to collect enough light to get a high quality spectrum and they have only been resently been identified as intersting.
@zQ4Z82W I'm not sure. I was under the impression that the JWST's NIRSpec could make these observations with sufficient observing time but I’m a theorist so don’t trust me here.
I’d be willing to extend the closing date if it’s not feasible to make this measurement in a year
Link to the preprint: https://arxiv.org/abs/2304.01173
