As we go from the center toward the surface of a neutron star, the state of baryonic matter changes from the deconfined quark-gluon to a mixed phase of quark and hadronic matter and a thin crust of hadronic matter. For the quark matter, within the MIT bag model, the total energy density of the system is the kinetic energy for noninteracting quarks plus a bag constant. In this article we consider a density-dependent bag constant obtained using the recent experimental results of CERN SPS on the formation of a quarkgluon plasma. For calculations of the hadron phase, we use the lowest-order constrained variational method. The equation of state of the mixed phase is determined using Gibbs conditions. Finally, we calculated the structure of a hot neutron star with quark core employing the TOV equation. Our results show that a density-dependent bag constant leads to a higher mass and lower radius for the hot neutron star with respect to the case where we use a fixed bag constant.
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References
A. Burrows and J. M. Lattimer, Astrophys. J., 307, 178, 1986.
N. K. Glendenning, Phys. Rev., D46, 1274, 1992.
A. Chodos, R. L. Jaffe, K. Johnson, C. B. Thorn, and V. F. Weisskopf, Phys. Rev., D9, 3471, 1974.
J. Rafelsky and B. Muller, Phys. Rev. Lett., 48, 1066, 1982.
T. Matsuiand and H. Satz, Phys. Lett., B178, 416, 1986.
J. Cleymans, R. V. Gavai, and E. Suhonen, Phys. Rep., 130, 217, 1986.
G. F. Burgio, M. Baldo, P. K. Sahu, and H.-J. Schulze, Phys. Rev., C66, 025802, 2002.
G. F. Burgio, M. Baldo, O. E. Nicotra, and H.-J. Schulze, Astrophys. J. Suppl. Ser., 308, 387, 2007.
G. H. Bordbar, M. Bigdeli, and T. Yazdizadeh, Int. J. Mod. Phys., A21, 5991, 2006.
G. H. Bordbar and M. Hayati, Int. J. Mod. Phys., A21, 1555, 2006.
T. Yazdizadeh and G. H. Bordbar, Res. Astron. Astrophys., 11, 471, 2011.
G. H. Bordbar and M. Modarres, J. Phys. G: Nucl. Phys., 23, 1631, 1997.
G. H. Bordbar and M. Modarres, Phys. Rev., C57, 714, 1998.
M. Modarres and G. H. Bordbar, Phys. Rev., C58, 2781, 1998.
G. H. Bordbar and M. Bigdeli, Phys. Rev., C75, 045804, 2007.
G. H. Bordbar and M. Bigdeli, Phys. Rev., C76, 035803, 2007.
G. H. Bordbar and M. Bigdeli, Phys. Rev., C77, 015805, 2008.
G. H. Bordbar and M. Bigdeli, Phys. Rev., C78, 054315, 2008.
M. Bigdeli, G. H. Bordbar, and Z. Rezaei, Phys. Rev., C80, 034310, 2009.
E. Farhi and R. L. Jaffe, Phys. Rev., D30, 2379, 1984.
U. Heinz and M. Jacobs, nucl-th/0002042.
U. Heinz, Nuch. phys., A685, 414, 2001.
C. Adami and G. E. Brown, Phys. Rep., 234, 1, 1993.
D. Blaschke, H. Grigorian, G. Poghosyan, C. D. Roberts, and S. Schmidt, Phys. Lett., B450, 207, 1999.
M. Baldo, G. F. Burgio, and H.-J. Schulze, Superdense QCD Matter and Compact Stars NATO Sci. Ser., Vol. 197, Part II, 113, 2006.
G. F. Burgio, M. Baldo, P. K. Sahu, A. B. Santra, and H.-J. Schulze, Phys. Lett., B526, 19, 2002.
S. L. Shapiro and S. A. Teukolski, Black Holes, White Dwarfs and Neutron Stars, New York, 1983.
N. K. Glendenning, Compact Star, Nuclear Physics, Particle Physics and General Relativity, Springer, New York, 2nd ed., 2000.
F. Weber, Pulsars as Astrophysical Laboratories for Nuclear and Particle Physics, Institute of Physics, Bristol, 1999.
G. Baym, C. Pethick, and P. Sutherland, Astrophys. J., 170, 299, 1971.
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Published in Astrofizika, Vol. 56, No. 1, pp. 134–141 (February 2013).
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Yazdizadeh, T., Bordbar, G.H. The Effect of a Density-Dependent Bag Constant on the Structure of a Hot Neutron Star with a Quark Core. Astrophysics 56, 121–129 (2013). https://doi.org/10.1007/s10511-013-9272-y
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DOI: https://doi.org/10.1007/s10511-013-9272-y