skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Gaps below strange star crusts

Abstract

The gap caused by a strong electric field between the quark surface and nuclear crust of a strange star is studied in an improved model including gravity and pressure as well as electrostatic forces. The transition from gap to crust is followed in detail. The properties of the gap are investigated for a wide range of parameters assuming both color-flavor locked and noncolor-flavor locked strange star cores. The maximally allowed crust density is generally lower than that of neutron drip. Finite temperature is shown to increase the gap width, but the effect is significant only at extreme temperatures. Analytical approximations are derived and shown to provide useful fits to the numerical results.

Authors:
;  [1]
  1. Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark)
Publication Date:
OSTI Identifier:
20774497
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. D, Particles Fields; Journal Volume: 72; Journal Issue: 12; Other Information: DOI: 10.1103/PhysRevD.72.123005; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; APPROXIMATIONS; COLOR MODEL; DENSITY; ELECTRIC FIELDS; FLAVOR MODEL; GRAVITATION; NEUTRON STARS; NEUTRONS; QUARKS

Citation Formats

Stejner, Morten, and Madsen, Jes. Gaps below strange star crusts. United States: N. p., 2005. Web. doi:10.1103/PhysRevD.72.123005.
Stejner, Morten, & Madsen, Jes. Gaps below strange star crusts. United States. doi:10.1103/PhysRevD.72.123005.
Stejner, Morten, and Madsen, Jes. Thu . "Gaps below strange star crusts". United States. doi:10.1103/PhysRevD.72.123005.
@article{osti_20774497,
title = {Gaps below strange star crusts},
author = {Stejner, Morten and Madsen, Jes},
abstractNote = {The gap caused by a strong electric field between the quark surface and nuclear crust of a strange star is studied in an improved model including gravity and pressure as well as electrostatic forces. The transition from gap to crust is followed in detail. The properties of the gap are investigated for a wide range of parameters assuming both color-flavor locked and noncolor-flavor locked strange star cores. The maximally allowed crust density is generally lower than that of neutron drip. Finite temperature is shown to increase the gap width, but the effect is significant only at extreme temperatures. Analytical approximations are derived and shown to provide useful fits to the numerical results.},
doi = {10.1103/PhysRevD.72.123005},
journal = {Physical Review. D, Particles Fields},
number = 12,
volume = 72,
place = {United States},
year = {Thu Dec 15 00:00:00 EST 2005},
month = {Thu Dec 15 00:00:00 EST 2005}
}
  • We construct strangelets, taking into account electrostatic effects, including Debye screening, and arbitrary surface tension {sigma} of the interface between vacuum and quark matter. We find that there is a critical surface tension {sigma}{sub crit} below which large strangelets are unstable to fragmentation and below which quark star surfaces will fragment into a crystalline crust made of charged strangelets immersed in an electron gas. We derive a model-independent relationship between {sigma}{sub crit} and two parameters that characterize any quark matter equation of state. For reasonable model equations of state, we find {sigma}{sub crit} typically of order a few MeV/fm{sup 2}.more » If {sigma}{<=}{sigma}{sub crit}, the size-distribution of strangelets in cosmic rays could feature a peak corresponding to the stable strangelets that we construct.« less
  • If strange quark matter is absolutely stable, some neutron stars may be strange quark stars. Strange quark stars are usually assumed to have a simple liquid surface. We show that if the surface tension of droplets of quark matter in the vacuum is sufficiently small, droplets of quark matter on the surface of a strange quark star may form a solid crust on top of the strange quark star. This solid crust can significantly modify the predictions for the photon emission for the surface in an observable way.
  • This article presents an investigation into the pycnonuclear reaction rates in dense crustal matter of neutron stars contaminated with strange quark matter nuggets. The presence of such nuggets in the crustal matter of neutron stars would be a natural consequence if Witten's strange quark matter hypothesis is correct. The methodology presented in this article is a recreation of a recent representation of nuclear force interactions embedded within pycnonuclear reaction processes. The study then extends the methodology to incorporate distinctive theoretical characteristics of strange quark matter nuggets, like their low charge-per-baryon ratio, and then assesses their effects on the pycnonuclear reactionmore » rates. Particular emphasis is put on the impact of color superconductivity on the reaction rates. Depending on whether quark nuggets are in this novel state of matter, their electric charge properties vary drastically, which turns out to have a dramatic effect on the pycnonuclear reaction rates. Future nuclear fusion network calculations may thus have the potential to shed light on the existence of strange quark matter nuggets and on whether they are in a color superconducting state, as suggested by QCD.« less
  • We investigate the specific heat of superfluid neutrons in the region of the crust of a neutron star characterized by unusual nuclear shapes, whose possible existence has been recently proposed. To describe pairing properties the results from Reid soft-core potential for nucleon-nucleon interaction are used. It is found that the presence of unusual nuclei causes a sizable increase in the specific heat. The results can have consequences in the study of thermal evolution of young neutron stars.