Year: 2025
Type: article
Abstract: We study the behaviour of the chameleon mechanism around white dwarfs and its impact on their structure. Using a shooting method of our own design, we solve the corresponding scalar–tensor equilibrium equations for a Chandrasekhar equation of state, exploring various energy scales and couplings of the chameleon field to matter. For the considered parameter ranges, we find the chameleon field to be in a thick-shell configuration, identifying for the first time in the literature a similarity relation of the theory for the radially normalised scalar field gradient. Our analysis reveals that the chameleon mechanism alters the pressure gradient of white dwarfs, leading to a reduction in the stellar radii and masses and shifting the mass–radius curves below those predicted by Newtonian gravity. This also lowers the specific heat of white dwarfs, accelerating their cooling process. Finally, we derive parametric expressions from our results to expedite future analyses of white dwarfs in scalar–tensor theories.
Source: Universe
Authors: Joan Bachs-Esteban, Ilídio Lopes, Javier Rubio
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,930
Awards: G2660406951, G332510590, G3404902608, G3480869486, G3497873372, G391908461, G4285760616, G4546701545, Collapsed structures in scalar-tensor theories of gravity, Centro de Astrofísica e Gravitação, G5454278309, G5615599820, G5815023779, G6276773425, G635614005, G7082142669, G7084143925, Quanto atractivo e a materia escura?, G785287643, G7854950945, G7991599336, G8920660035
OpenAlex ID: W4412512502