scholarly journals Holographic equations of state and astrophysical compact objects

2011 ◽  
Vol 2011 (10) ◽  
Author(s):  
Youngman Kim ◽  
Chang-Hwan Lee ◽  
Ik Jae Shin ◽  
Mew-Bing Wan
Keyword(s):  
Equations Of State ◽  
Compact Objects

scholarly journals Stability and improved physical characteristics of relativistic compact objects arising from the quadratic term in $$p_r = \alpha \rho ^2 + \beta \rho - \gamma $$

2021 ◽  
Vol 81 (1) ◽  
Author(s):  
S. Thirukkanesh ◽  
Robert S. Bogadi ◽  
Megandhren Govender ◽  
Sibusiso Moyo
Keyword(s):  
Equation Of State ◽  
Gravitational Potential ◽  
Equations Of State ◽  
Quadratic Equation ◽  
Physical Characteristics ◽  
Compact Objects ◽  
Quadratic Term ◽  
Stellar Objects ◽  
Quadratic Equation Of State ◽  
The Stability

AbstractWe investigate the stability and enhancement of the physical characteristics of compact, relativistic objects which follow a quadratic equation of state. To achieve this, we make use of the Vaidya–Tikekar metric potential. This gravitational potential has been shown to be suitable for describing superdense stellar objects. Pressure anisotropy is also a key feature of our model and is shown to play an important role in maintaining stability. Our results show that the combination of the Vaidya–Tikekar gravitational potential used together with the quadratic equation of state provide models which are favourable. In comparison with other equations of state, we have shown that the quadratic equation of state mimics the colour-flavour-locked equation of state more closely than the linear equation of state.

scholarly journals Distinct classes of compact stars based on geometrically deduced equations of state

2021 ◽  
pp. 2150029
Author(s):  
A. C. Khunt ◽  
V. O. Thomas ◽  
P. C. Vinodkumar
Keyword(s):  
Neutron Stars ◽  
Soft Matter ◽  
Equations Of State ◽  
Compact Objects ◽  
Exotic Matter ◽  
Compact Stars ◽  
Spacetime Geometry ◽  
Superdense Stars ◽  
Einstein's Equation ◽  
Envelope Model

We have computed the properties of compact objects like neutron stars based on equation of state (EOS) deduced from a core–envelope model of superdense stars. Such superdense stars have been studied by solving Einstein’s equation based on pseudo-spheroidal and spherically symmetric spacetime geometry. The computed star properties are compared with those obtained based on nuclear matter EOSs. From the mass–radius ([Formula: see text]–[Formula: see text]) relationship obtained here, we are able to classify compact stars in three categories: (i) highly compact self-bound stars that represents exotic matter compositions with radius lying below 9[Formula: see text]km; (ii) normal neutron stars with radius between 9 to 12[Formula: see text]km and (iii) soft matter neutron stars having radius lying between 12 to 20[Formula: see text]km. Other properties such as Keplerian frequency, surface gravity and surface gravitational redshift are also computed for all the three types. This work would be useful for the study of highly compact neutron like stars having exotic matter compositions.

WARM STELLAR MATTER: APPLICATION TO SLOWLY ROTATING COMPACT OBJECTS

2008 ◽  
Vol 23 (05) ◽  
pp. 729-740
Author(s):  
M. D. ALLOY ◽  
D. P. MENEZES
Keyword(s):  
Equations Of State ◽  
Compact Objects ◽  
Zero Temperature ◽  
Stellar Matter

In the present paper we investigate one possible variation on the usual static pulsars: the inclusion of rotation. We use a formalism proposed by Hartle and Thorne to calculate the properties of rotating pulsars with all possible compositions. The calculations were performed for both zero temperature and for fixed entropy equations of state.

scholarly journals Strange stars in energy–momentum-conserved f(R,T) gravity

2020 ◽  
Vol 29 (10) ◽  
pp. 2050075
Author(s):  
G. A. Carvalho ◽  
S. I. Dos Santos ◽  
P. H. R. S. Moraes ◽  
M. Malheiro
Keyword(s):  
Energy Momentum Tensor ◽  
Equations Of State ◽  
Linear Equations ◽  
Momentum Tensor ◽  
Compact Objects ◽  
Strange Stars ◽  
Cosmological Scenario ◽  
Astrophysical Objects ◽  
Tensor Formula ◽  
Tov Equation

For the accurate understanding of compact astrophysical objects, the Tolmann–Oppenheimer–Volkoff (TOV) equation has proved to be of great use. Nowadays, it has been derived in many alternative gravity theories, yielding the prediction of different macroscopic features for such compact objects. In this work, we apply the TOV equation of the energy–momentum–conserved version of the [Formula: see text] gravity theory to strange quark stars. The [Formula: see text] theory, with [Formula: see text] being a generic function of the Ricci scalar [Formula: see text] and trace of the energy–momentum tensor [Formula: see text] to replace [Formula: see text] in the Einstein–Hilbert gravitational action, has shown to provide a very interesting alternative to the cosmological constant [Formula: see text] in a cosmological scenario, particularly in the energy–momentum conserved case (a general [Formula: see text] function does not conserve the energy–momentum tensor). Here, we impose the condition [Formula: see text] to the astrophysical case, particularly the hydrostatic equilibrium of strange stars. We solve the TOV equation by taking into account linear equations of state to describe matter inside strange stars, such as [Formula: see text] and [Formula: see text], known as the MIT bag model, with [Formula: see text] the pressure and [Formula: see text] the energy density of the star, [Formula: see text] constant and [Formula: see text] the bag constant.

TPT2 and SAFTD equations of state for mixtures of hard chain copolymers

2000 ◽  
Vol 98 (24) ◽  
pp. 2045-2052
Author(s):  
Keshawa P. Shukla, Walter G. Chapman
Keyword(s):  
Equations Of State

Computation of flows with arbitrary equations of state

AIAA Journal ◽  
1998 ◽  
Vol 36 ◽  
pp. 515-521 ◽  
Author(s):  
Charles L. Merkle ◽  
Philip E. O. Buelow ◽  
Sankaran Venkateswaran ◽  
Jennifer Y. Sullivan
Keyword(s):  
Equations Of State

SITE-SPECIFIC EQUATIONS OF STATE FOR COASTAL SEA AREAS AND INLAND WATER BODIES

2017 ◽  
Author(s):  
Natalia Andrulionis ◽  
Natalia Andrulionis ◽  
Ivan Zavialov ◽  
Ivan Zavialov ◽  
Elena Kovaleva ◽  
...  
Keyword(s):  
Equation Of State ◽  
Black Sea ◽  
Water Samples ◽  
Equations Of State ◽  
Sea Water ◽  
Ionic Composition ◽  
Water Bodies ◽  
Aral Sea ◽  
The Black Sea ◽  
Coastal Sea

This article presents a new method of laboratory density determination and construction equations of state for marine waters with various ionic compositions and salinities was developed. The validation of the method was performed using the Ocean Standard Seawater and the UNESCO thermodynamic equation of state (EOS-80). Density measurements of water samples from the Aral Sea, the Black Sea and the Issyk-Kul Lake were performed using a high-precision laboratory density meter. The obtained results were compared with the density values calculated for the considered water samples by the EOS-80 equation. It was shown that difference in ionic composition between Standard Seawater and the considered water bodies results in significant inaccuracies in determination of water density using the EOS-80 equation. Basing on the laboratory measurements of density under various salinity and temperature values we constructed a new equation of state for the Aral Sea and the Black Sea water samples and estimated errors for their coefficients.

Sign in / Sign up

Export Citation Format

Share Document