White dwarf bounds on charged massive particles

Abstract

White dwarfs effectively act as high-gain amplifiers for relatively small energy deposits within their volume via their supernova instability. In this paper, we consider the ways a galactic abundance of O(1)-charged massive relics (i.e., CHAMPs) could trigger this instability, thereby destroying old WD. The dense central core structure formed inside the WD when heavy CHAMPs sink to its center can trigger a supernova via injection of energy during collapse phases, via direct density-enhanced (pycnonuclear) fusion processes of carbon nuclei dragged into the core by the CHAMPs, or via the formation of a black hole (BH) at the center of the WD. In the latter scenario, Hawking radiation from the BH can ignite the star if the BH forms with a sufficiently small mass; if the BH instead forms at large enough mass, heating of carbon nuclei that accrete onto the BH as it grows in size may be able to achieve the same outcome (with the conservative alternative being simply that the WD is devoured by the BH). The known existence of old WD that have not been destroyed by these mechanisms allows us to improve by many orders of magnitude on the existing CHAMP abundance constraints in the regime of large CHAMP mass, mX ∼ 10 11 -10 18 GeV. Additionally, in certain regions of parameter space, we speculate that this setup could provide a trigger mechanism for the calcium-rich gap transients: a class of anomalous, sub-luminous supernova events that occur far outside of a host galaxy.

Dark matter scattering in astrophysical media: collective effects

“…To understand this process, one needs to understand the initial capture of the DM, and its subsequent scattering inside the WD, both with the SM medium and with other DM particles. Alternatively, the decay of very heavy DM particles inside WDs [46] (or other kinds of energy injection processes [47,48]) could ignite supernovae. We leave analysis of such possibilities to future work.…”

Constraints on Relic Magnetic Black Holes

“…The hot, dense conditions inside of Carbon-Oxygen (CO) white dwarfs make them very sensitive to small energy injections [24]. For example, depositing ∼ 6 × 10 21 GeV within a region of radius of ∼ 6 × 10 −3 cm in a time less than ∼ 3 × 10 −12 s leads to runaway fusion in white dwarfs with masses above 1M , destroying the white dwarf in a supernova explosion [24][25][26]. We will use this sensitivity to put bounds on EMBH densities from the observation of old white dwarfs in the galaxy.…”

Accelerating Composite Dark Matter Discovery with Nuclear Recoils and the Migdal Effect

“…In this context, there have been several proposals for dark sectors capable of igniting a thermonuclear runaway in single sub-Chansdrasekhar white dwarfs as possible solutions to this problem. These include accumulation and collapse of asymmetric dark matter cores that transfer their gravitational energy via dark matter-nucleus scattering [57][58][59], evaporation to Hawking radiation of black holes formed from the collapsed dark matter cores [58,59], heavy dark matter annihilation or decay to Standard Model particles [60], pycnonuclear reactions enhanced by charged massive particles [61], and the transit of primordial black holes [62,63] (see also [64][65][66][67][68][69][70][71][72][73][74] for related work on dark matter in white dwarf stars).…”

“…where σ SB = π 2 /60 is the Stefan-Boltzmann constant in natural units, and κ r 10 7 cm 2 g −1 (T * /10 7 K) −7/2 (ρ * /10 9 g cm −3 ) is the white dwarf radiative opacity for free-free electron transitions [61,78]. In the second equality, we have approximated the temperature gradient…”