Stars Within Stars: The Interplay Between Main-Sequence Stars and Dark Matter
Abstract
Asymmetric dark matter may form self-gravitating macroscopic structures called dark stars if its microscopic properties give rise to sufficient effective pressure to counteract gravity. We study low-mass baryonic stars embedded within such dark stars, treating the baryonic and dark components as two gravitating fluids. The dark sector is assumed to be non-luminous and to interact with the baryonic star only through gravity, while the baryonic structure is computed using a realistic equation of state, opacity tables, and proton-proton-chain energy production. We find that the additional gravitational potential increases the luminosity at fixed baryonic mass, as the baryons must reach higher temperatures to maintain hydrostatic equilibrium. This lowers the minimum baryonic mass for hydrogen-burning configurations below the standard value of ∼0.085M⊙. The resulting increase in luminosity can reduce the estimated main-sequence lifetime significantly, bringing low-mass configurations that would otherwise remain on the main sequence for hundreds of Gyr to cosmologically relevant timescales. We further show that photons escaping from the stellar surface undergo gravitational redshift determined by the global dark matter mass distribution. Consequently, extended dark star configurations can produce distinct observational signatures even when their outer regions have little effect on the intrinsic baryonic stellar structure, providing a potential probe of otherwise hidden dark structures.
Related
- Characterizing NGC 6383: Study of fundamental properties,pre-main sequence stars, mass segregation, and age using Gaia DR3 and 2MASS
- Super-Chandrasekhar white dwarfs by the evolution of magnetized main-sequence stars: New mass-limits from STARS simulation
- Super-Chandrasekhar White Dwarfs by the Evolution of Magnetized Main-sequence Stars: New Mass Limits from STARS Simulation
- Re-calibrated analytic stellar evolution formulae for the main sequence: Extension to massive stars and variations in [α/Fe]
- Evolution of Massive Main-Sequence Stars in Binary Population Synthesis. II. Consequences for Black Hole High-Mass X-ray Binaries and Binary Black Holes
BibTeX
@misc{kamenetskaia2026stars,
title = {{Stars Within Stars: The Interplay Between Main-Sequence Stars and Dark Matter}},
author = {Boris Betancourt Kamenetskaia and Chris Kouvaris},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.07136},
eprint = {2611.07136},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.07136},
}
RIS
TY - UNPB
TI - Stars Within Stars: The Interplay Between Main-Sequence Stars and Dark Matter
AU - Boris Betancourt Kamenetskaia
AU - Chris Kouvaris
PY - 2026
DA - 2026/11/04
PB - arXiv
DO - 10.48550/arxiv.2611.07136
UR - https://arxiv.org/abs/2611.07136
AB - Asymmetric dark matter may form self-gravitating macroscopic structures called dark stars if its microscopic properties give rise to sufficient effective pressure to counteract gravity. We study low-mass baryonic stars embedded within such dark stars, treating the baryonic and dark components as two gravitating fluids. The dark sector is assumed to be non-luminous and to interact with the baryonic star only through gravity, while the baryonic structure is computed using a realistic equation of state, opacity tables, and proton-proton-chain energy production. We find that the additional gravitational potential increases the luminosity at fixed baryonic mass, as the baryons must reach higher temperatures to maintain hydrostatic equilibrium. This lowers the minimum baryonic mass for hydrogen-burning configurations below the standard value of ∼0.085M_⊙. The resulting increase in luminosity can reduce the estimated main-sequence lifetime significantly, bringing low-mass configurations that would otherwise remain on the main sequence for hundreds of Gyr to cosmologically relevant timescales. We further show that photons escaping from the stellar surface undergo gravitational redshift determined by the global dark matter mass distribution. Consequently, extended dark star configurations can produce distinct observational signatures even when their outer regions have little effect on the intrinsic baryonic stellar structure, providing a potential probe of otherwise hidden dark structures.
ER -