Thermal evolution of neo-neutron stars. II. Temperature-dependent crusts
Year: 2026
Type: article
Abstract: The neo-neutron star phase is an intermediate stage in the evolution from a hot, lepton-rich compact object, which is formed in the aftermath of a core-collapse supernova or an accretion-induced collapse of a white dwarf, to a cold deleptonized neutron star (NS). Alternatively, this phase can occur after a binary NS merger if the final compact object does not collapse immediately into a black hole. Radial temperature profiles provided by numerical simulations of proto-NS evolution suggest that the composition and mechanical structure of the star's core at the beginning of the neo-NS phase are approximately identical to those of a cold NS. In contrast, the composition and mechanical structure of the outer layers (i.e., the crust) are expected to change as the star cools. The thermal evolution of neo-NSs with temperature-dependent (inner) envelopes was considered by . Beznogov_ApJ_2020 Here, we investigate what happens if the equation of state (EoS) of the entire crust, including its composition, depends on temperature. We analyzed the thermal, mechanical, and chemical evolution of neo-NSs by further developing and employing , our NS thermal evolution code. neo-NSCool First, we show that thermally dripped neutrons slightly slow down the cooling during the early thermal relaxation stage. Then, we demonstrate that the EoSs featuring exotic light species in the deepest layers of the crust result in significantly slower cooling in the photon-cooling era compared to the EoSs that favor massive nuclei. The crust's composition also impacts the crystallization process as well as the contraction of the crust during cooling. The EoSs with light nuclei cause the innermost layers to remain liquid for a longer time than the EoSs with heavy nuclei.
Source: Astronomy and Astrophysics
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,865
Funders: Universidad Nacional Autónoma de México, Unitatea Executiva pentru Finantarea Invatamantului Superior, a Cercetarii, Dezvoltarii si Inovarii, Ministry of Education and Research, Romania, Dirección General de Asuntos del Personal Académico, Universidad Nacional Autónoma de México, Colegiul Consultativ pentru Cercetare-Dezvoltare şi Inovare
Awards: G5981306442, G6185973520, G8758052483
OpenAlex ID: W7197053405