scholarly journals Evolution of White Dwarfs and their Physics

1979 ◽  
Vol 53 ◽  
pp. 11-32
Author(s):  
Giora Shaviv
Keyword(s):  
Equation Of State ◽  
Physical Properties ◽  
White Dwarfs ◽  
Dense Matter ◽  
Space Time ◽  
Stellar Structure ◽  
Physical Problems ◽  
Partially Ionized

White Dwarfs (WD) are one of the fields in stellar structure in which the so-called “input physics” is not yet completely clear today. In particular the equation of state (EOS) of WD affects directly one of the eminent problems in present day research of WD, namely is the “paucity” of low luminosity WD real? The reply depends in a sensitive way on the physical properties of the dense matter. For this reason we go in some detail into the physical problems of the “input physics”. We distinguish between the problem of the interior-fully ionized matter and the envelope-partially ionized matter. Unfortunately space-time is not sufficient to cover in any detail the EOS of the envelope although this problem is extremely important to the evolution.

scholarly journals Equations of State in Stellar Structure and Evolution

1994 ◽  
Vol 147 ◽  
pp. 1-15
Author(s):  
H. M. Van Horn
Keyword(s):  
Phase Transition ◽  
Equation Of State ◽  
White Dwarfs ◽  
Equations Of State ◽  
Dense Matter ◽  
Reaction Rates ◽  
Stellar Structure ◽  
First Order ◽  
First Order Phase Transition ◽  
First Order Phase

AbstractIn this paper I summarize some of the recent advances in studies of dense matter. Research on phase separation in the binary ionic mixtures (BIMs) that constitute the matter in white dwarfs has been motivated by the need to obtain accurate estimates for the ages of the faintest white dwarfs and thus of the disk of our Galaxy. Substantial age increases appear possible, but it is not yet clear whether such large increases occur in real white dwarfs. A second advance is the prediction, based on state-of-the-art physical calculations, that ionization of H at low temperatures and increasing densities may occur via a first-order “plasma phase transition” (PPT). Astrophysical consequences of this result are still being explored in an effort to test this prediction. Related to these equation-of-state calculations are calculations of the enhancement of nuclear reaction rates at high densities. New thermonuclear rates have been computed for C+C reactions in BIMs, although there is currently some controversy about results at the highest densities. New pycnonuclear reaction rates have also been calculated for BIMs, and it has been suggested that He-burning at T = 0 may occur through a first-order phase transition. Finally, calculations of the equation of state of matter in strong magnetic fields and of radiative opacities at high densities have undergone very recent and substantial improvements, which are just beginning to be utilized in astrophysical calculations.

scholarly journals Thermonuclear burst oscillations and the dense matter equation of state

2017 ◽  
Vol 13 (S337) ◽  
pp. 209-212
Author(s):  
Anna L. Watts
Keyword(s):  
Equation Of State ◽  
Relativistic Effects ◽  
Dense Matter ◽  
Stellar Structure ◽  
Large Area ◽  
Pulse Profile ◽  
Oscillation Mechanism ◽  
Thermonuclear Explosion ◽  
Structure Equations ◽  
Area X

AbstractMatter in neutron star cores reaches extremely high densities, forming states of matter that cannot be generated in the laboratory. The Equation of State (EOS) of the matter links to macroscopic observables, such as mass M and radius R, via the stellar structure equations. A promising technique for measuring M and R exploits hotspots (burst oscillations) that form on the stellar surface when material accreted from a companion star undergoes a thermonuclear explosion. As the star rotates, the hotspot gives rise to a pulsation, and relativistic effects encode information about M and R into the pulse profile. However the burst oscillation mechanism remains unknown, introducing uncertainty when inferring the EOS. I review the progress that we are making towards cracking this long-standing problem, and establishing burst oscillations as a robust tool for measuring M and R. This is a major goal for future large area X-ray telescopes.

scholarly journals From Taub-NUT to Kaluza-Klein magnetic monopole

2016 ◽  
Vol 41 ◽  
pp. 1660121
Author(s):  
Nematollah Riazi ◽  
S. Sedigheh Hashemi
Keyword(s):  
Equation Of State ◽  
Physical Properties ◽  
Event Horizon ◽  
Magnetic Monopole ◽  
Vacuum Solution ◽  
Space Time ◽  
Negative Mass ◽  
Five Dimensions ◽  
Kaluza Klein

We present a Kaluza-Klein vacuum solution which closely resembles the Taub-NUT magnetic monopole and we investigate its physical properties as viewed from four space-time dimensions. We show that the Taub-NUT Kaluza-Klein vacuum solution in five dimensions is a static magnetic monopole. We find that the four dimensional matter properties do not obey the equation of state of radiation and there is no event horizon. A comparison with the available magnetic monopole solutions and the issue of vanishing and negative mass are discussed.

scholarly journals Determination of the Equation of State of Dense Matter

Science ◽  
2002 ◽  
Vol 298 (5598) ◽  
pp. 1592-1596 ◽  
Author(s):  
P.&l. Danielewicz
Keyword(s):  
Equation Of State ◽  
Dense Matter

scholarly journals An equation of state for partially ionized plasmas: The Coulomb contribution to the free energy

2015 ◽  
Vol 16 ◽  
pp. 36-40 ◽  
Author(s):  
D.P. Kilcrease ◽  
J. Colgan ◽  
P. Hakel ◽  
C.J. Fontes ◽  
M.E. Sherrill
Keyword(s):  
Free Energy ◽  
Equation Of State ◽  
Ionized Plasmas ◽  
Partially Ionized Plasmas ◽  
Partially Ionized ◽  
Coulomb Contribution

OF CHARGED STARS AND CHARGED BLACK HOLES

2004 ◽  
Vol 13 (07) ◽  
pp. 1375-1379 ◽  
Author(s):  
MANUEL MALHEIRO ◽  
RODRIGO PICANÇO ◽  
SUBHARTHI RAY ◽  
JOSÉ P. S. LEMOS ◽  
VILSON T. ZANCHIN
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Charged Particle ◽  
Equation Of State ◽  
Mass Density ◽  
Compact Star ◽  
Maximum Amount ◽  
Stellar Structure ◽  
Charged Black Holes ◽  
Polytropic Equation

Effect of maximum amount of charge a compact star can hold, is studied here. We analyze the different features in the renewed stellar structure and discuss the reasons why such huge charge is possible inside a compact star. We studied a particular case of a polytropic equation of state (EOS) assuming the charge density is proportional to the mass density. Although the global balance of force allows a huge charge, the electric repulsion faced by each charged particle forces it to leave the star, resulting in the secondary collapse of the system to form a charged black hole.

Optical and physical properties of hydrocarbons with metal impurities in the warm dense matter regime

2021 ◽  
Vol 28 (2) ◽  
pp. 022705
Author(s):  
Yu Cao ◽  
Yanyun Chu ◽  
Zhen Wang ◽  
Jianmin Qi ◽  
Lin Zhou ◽  
...  
Keyword(s):  
Physical Properties ◽  
Dense Matter ◽  
Warm Dense Matter ◽  
Metal Impurities
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