Polytropic spheres containing regions of trapped null geodesics
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F47813059%3A19240%2F17%3AA0000026" target="_blank" >RIV/47813059:19240/17:A0000026 - isvavai.cz</a>
Result on the web
<a href="https://journals.aps.org/prd/abstract/10.1103/PhysRevD.95.043009" target="_blank" >https://journals.aps.org/prd/abstract/10.1103/PhysRevD.95.043009</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1103/PhysRevD.95.043009" target="_blank" >10.1103/PhysRevD.95.043009</a>
Alternative languages
Result language
angličtina
Original language name
Polytropic spheres containing regions of trapped null geodesics
Original language description
We demonstrate that in the framework of standard general relativity, polytropic spheres with properly fixed polytropic index n and relativistic parameter sigma, giving a ratio of the central pressure p_(c) to the central energy density rho_(c), can contain a region of trapped null geodesics. Such trapping polytropes can exist for n > 2.138, and they are generally much more extended and massive than the observed neutron stars. We show that in the n-sigma parameter space, the region of allowed trapping increases with the polytropic index for intervals of physical interest, 2.138 < n < 4. Space extension of the region of trapped null geodesics increases with both increasing n and sigma > 0.677 from the allowed region. In order to relate the trapping phenomenon to astrophysically relevant situations, we restrict the validity of the polytropic configurations to their extension rextr corresponding to the gravitational mass M similar to 2M_(circle dot) of the most massive observed neutron stars. Then, for the central density rho(c) similar to 10^(15) g cm^(-3), the trapped regions are outside r_extr for all values of 2.138 < n < 4; for the central density rho_(c) similar to 5 x 10^(15) g cm^(-3), the whole trapped regions are located inside r_(extr) for 2.138 < n < 3.1; while for rho_(c) similar to 10^(16) g cm^(-3), the whole trapped regions are inside r_(extr) for all values of 2.138 < n < 4, guaranteeing astrophysically plausible trapping for all considered polytropes. The region of trapped null geodesics is located close to the polytrope center and could have a relevant influence on the cooling of such polytropes or binding of gravitational waves in their interior.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10308 - Astronomy (including astrophysics,space science)
Result continuities
Project
<a href="/en/project/GB14-37086G" target="_blank" >GB14-37086G: Albert Einstein Center for Gravitation and Astrophysics</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>S - Specificky vyzkum na vysokych skolach<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace
Others
Publication year
2017
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Physical Review D
ISSN
2470-0010
e-ISSN
2470-0029
Volume of the periodical
95
Issue of the periodical within the volume
4
Country of publishing house
US - UNITED STATES
Number of pages
11
Pages from-to
'043009-1'-'043009-11'
UT code for WoS article
000396026700001
EID of the result in the Scopus database
2-s2.0-85022014008