ITC Colloquium - Ken Van Tilburg (Flatiron)


Thursday, April 14, 2022, 11:00am to 12:00pm



"Stellar Basins of Gravitationally Bound Particles"

I will describe the phenomenology of stellar basins: volumetric stellar emission into gravitationally bound orbits of weakly coupled particles such as axions, moduli, hidden photons, and fermions. While only a tiny fraction of the instantaneous luminosity of a star (the vast majority of the emission is into relativistic modes), the continual injection of these particles into a small part of phase space causes them to accumulate over astrophysically long time scales, forming a "stellar basin", in analogy with the geologic kind. I will argue that stellar basins (will) form the basis of the leading probes for almost any exotic particle if its rest mass is of order a keV. For example, the energy density of the Solar basin can surpass that of the relativistic Solar flux at Earth's location after only a million years, for a sufficiently long-lived particle produced through an emission process whose matrix elements are unsuppressed at low momentum. I will discuss ongoing N-body simulations of the Solar basin, preliminary results on indirect detection with X-rays, and recasted direct detection searches for basin particles around the Sun.

See also: Colloquium, 2021-22