Year: 2026
Type: preprint
Abstract: A sufficiently strong hadron-to-quark first-order phase transition can give rise to a third family of stable compact stars that are commonly referred to as hybrid hadron-quark stars. Stable hybrid stars that have the same gravitational mass as neutron stars are referred to as twin stars. Although equilibrium twin stars may exist, whether they can be dynamically formed remains an open question. We investigate this problem by examining the gravitational binding energy of competing equilibrium configurations at fixed baryonic rest mass and by performing general relativistic hydrodynamical simulations of several possible transition channels. While twin stars are more gravitationally bound than neutron stars with the same rest mass, this energetic preference alone does not determine the dynamical outcome. Compression and shocks during the evolution generate thermal pressure that can prevent the system from settling on the cold twin star branch. Our simulations show that sufficiently rapid cooling can remove this thermal support and enable twin star formation, whereas slower or no cooling generally favors a neutron star remnant. Accessing the twin star branch through the formation channels considered here requires cooling on a timescale comparable to or shorter than the stellar dynamical timescale. Since realistic cooling mechanisms operate on much longer timescales, our results suggest that in channels that conserve the total rest-mass neutron stars may be dynamically favored even when a more gravitationally bound twin star configuration exists with the same rest mass. Our results demonstrate a point of principle, at least for equations of state where the quark deconfinement density does not change appreciably for temperatures up to $10-20\,\textrm{MeV}.$
Source: arXiv (Cornell University)
Authors: Naseri, Mahdi, Paschalidis, Vasileios
Institution: University of Arizona
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G1453181110, G1693976111, Track 4: Advanced CI Coordination Ecosystem: Monitoring and Measurement Services, G2815302120, G3339971651, G3562386289, CAREER: Research in Strong-Field Gravity and Astrophysics, Track 1: ACCESS Resource Allocations Marketplace and Platform Services (RAMPS), G4010157413, G4248962021, ACO: An Open CI Ecosystem to Advance Scientific Discovery (OpenCI), Track 3: COre National Ecosystem for CyberinfrasTructure (CONECT), G5367127336, G5464919783, G6128126499, G6385132645, Track 2: Customized Multi-tier Assistance, Training, and Computational Help (MATCH) for End User ACCESS to CI, G8614379466
OpenAlex ID: W7213394548