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We perform one-zone simulations of the infall epoch of a pre-supernova stellar core in the presence of neutrino flavor changing scattering interactions. Our calculations give a self-consistent assessment of the relationship between flavor…

Astrophysics · Physics 2008-11-26 Philip S. Amanik , George M. Fuller

We describe a new method to incorporate thermonuclear heating in the envelope of accreting neutron star into long term simulations of their thermal evolution. We obtain boundary conditions for the heat exchange between the envelope and the…

High Energy Astrophysical Phenomena · Physics 2025-09-01 Martin Nava-Callejas , Dany Page , Yuri Cavecchi

In this work, we extend our previous study of the bulk viscosity of hot and dense $npe$ matter induced by the Urca processes in the neutrino trapped regime to $npe\mu$ matter by adding the muonic Urca processes as well as the purely…

High Energy Astrophysical Phenomena · Physics 2021-11-23 Mark Alford , Arus Harutyunyan , Armen Sedrakian

The rates of flavor-changing weak processes are crucial in determining the conditions of beta equilibrium in neutron stars and mergers, influencing the damping of oscillations, the stability of rotating pulsars, and the emission of…

Nuclear Theory · Physics 2024-11-25 Carlos Hoyos , Andrea Olzi , David Rodriguez-Fernandez

The neutron-drip transition in the dense matter constituting the interior of neutron stars generally refers to the appearance of unbound neutrons as the matter density reaches some threshold density $\rho_\textrm{drip}$. This transition has…

High Energy Astrophysical Phenomena · Physics 2015-05-27 N. Chamel , A. F. Fantina , J. L. Zdunik , P. Haensel

In this work we consider the role of muons in various URCA processes relevant for neutrino emissions in the core region of neutron stars. The calculations are done for $\beta$--stable nuclear matter with and without muons. We find muons to…

Nuclear Theory · Physics 2009-10-28 O. Elgaroy , L. Engvik , E. Osnes , F. V. De Blasio , M. Hjorth-Jensen , G. Lazzari

In this paper, we discuss the damping of density oscillations in dense nuclear matter in the temperature range relevant to neutron star mergers. This damping is due to bulk viscosity arising from the weak interaction ``Urca'' processes of…

Nuclear Theory · Physics 2020-06-23 Mark Alford , Arus Harutyunyan , Armen Sedrakian

Thermal evolution of neutron stars is studied in the $f(R)=R+\alpha R^{2}$ theory of gravity. We first describe the equations of stellar structure and evolution for a spherically symmetric spacetime plus a perfect fluid at rest. We then…

General Relativity and Quantum Cosmology · Physics 2023-06-08 Martín Nava-Callejas , Dany Page , Mikhail V. Beznogov

Historically, a sequence of nuclear pasta shapes was predicted to appear in the deepest region of the inner crust of a neutron star within the compressible liquid-drop picture, when the filling fraction $u$ exceeds some threshold values.…

High Energy Astrophysical Phenomena · Physics 2025-05-27 Nikolai N. Shchechilin , Nicolas Chamel , Andrey I. Chugunov

We study the flavor evolution of a dense gas initially consisting of pure mono-energetic $\nu_e$ and $\bar\nu_e$. Using adiabatic invariants and the special symmetry in such a system we are able to calculate the flavor evolution of the…

Astrophysics · Physics 2008-11-26 Huaiyu Duan , George M. Fuller , J. Carlson , Yong-Zhong Qian

We study the cooling of hybrid stars coupling with spin-down. Due to the spin-down of hybrid stars, the interior density continuously increases, different neutrino reactions may be triggered(from the modified Urca process to the quark and…

High Energy Astrophysical Phenomena · Physics 2014-11-20 Kang Miao , Wang Xiao-Dong , Pan Na-Na

The interior of a neutron star is expected to exhibit different states of matter. In particular, complex non-spherical configurations known as `pasta' phases may exist at the highest densities in the inner crust, potentially having an…

Nuclear Theory · Physics 2021-10-28 H. Dinh Thi , T. Carreau , A. F. Fantina , F. Gulminelli

We study the effect of asymmetric fermionic dark matter (DM) on the thermal evolution of neutron stars (NSs). No interaction between DM and baryonic matter is assumed, except the gravitational one. Using the two-fluid formalism, we show…

High Energy Astrophysical Phenomena · Physics 2024-03-08 Afonso Ávila , Edoardo Giangrandi , Violetta Sagun , Oleksii Ivanytskyi , Constança Providência

Our understanding of neutrino flavor conversion in the supernova core is still preliminary, despite its likely relevance to the neutrino-driven supernova mechanism. We present multi-angle and multi-energy numerical simulations of neutrino…

High Energy Astrophysical Phenomena · Physics 2024-09-25 Shashank Shalgar , Irene Tamborra

The rapid-neutron capture process ($r$ process) is identified as the producer of about 50\% of elements heavier than iron. This process requires an astrophysical environment with an extremely high neutron flux over a short amount of time…

Nuclear Experiment · Physics 2019-06-26 A. C. Larsen , A. Spyrou , S. N. Liddick , M. Guttormsen

We present a calculation of the neutrino-nucleon scattering cross section which takes into account the nuclear correlations in the relativistic random phase approximation. Our approach is based on a quantum hadrodynamics model with exchange…

Nuclear Theory · Physics 2007-05-23 L. Mornas , A. Perez

A comprehensive microscopic study of the properties of bulk matter at densities just below nuclear saturation $\rho_s = 2.5 \sim 10^{14}$ g cm$^{-3}$, zero and finite temperature and high neutron fraction, is outlined, and preliminary…

Astrophysics · Physics 2008-12-18 W. G. Newton

In this chapter, I describe bulk viscosity as a general concept, and then focus on bulk viscosity in the dense matter present in compact objects. While this review is focused on bulk viscosity in the conditions present in neutron star…

Nuclear Theory · Physics 2024-07-24 Steven P. Harris

We present a global linear stability analysis of nuclear fuel accumulating on the surface of an accreting neutron star and we identify the conditions under which thermonuclear bursts are triggered. The analysis reproduces all the recognized…

Astrophysics · Physics 2009-11-07 Ramesh Narayan , Jeremy S. Heyl

With the successful launch of Chandra and XMM/Newton X-ray space missions combined with the lower-energy band observations, we are in the position where careful comparison of neutron star cooling theories with observations will make it…

Astrophysics · Physics 2009-11-07 S. Tsuruta , M. A. Teter , T. Takatsuka , T. Tatsumi , R. Tamagaki