Direct Urca Processes with Hyperons in Cooling Neutron Stars
XU Yan1, LIU Guang-Zhou1**, WU Yao-Rui1, ZHU Ming-Feng1, YU Zi2, WANG Hong-Yan1, ZHAO En-Guang3
1 Center for Theoretical Physics, Jilin University, Changchun 130012 2 College of Science, Nanjing Forestry University, Nanjing 210037 3 Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190
Direct Urca Processes with Hyperons in Cooling Neutron Stars
XU Yan1, LIU Guang-Zhou1**, WU Yao-Rui1, ZHU Ming-Feng1, YU Zi2, WANG Hong-Yan1, ZHAO En-Guang3
1 Center for Theoretical Physics, Jilin University, Changchun 130012 2 College of Science, Nanjing Forestry University, Nanjing 210037 3 Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190
摘要In the relativistic mean field approximation, the relativistic energy losses of the direct Urca processes with nucleons (N-DURCA) and hyperons (Y-DURCA) are studied in the degenerate baryon matter of neutron stars. We investigate the effects of hyperon degrees of freedom and the Y-DURCA processes on the N-DURCA processes, and the total neutrino emissivity of neutron star matter. The results show that the existence of hyperons decreases the abundance of protons and leptons, and can sharply suppress the neutrino emissivity of the N-DURCA processes.
Abstract：In the relativistic mean field approximation, the relativistic energy losses of the direct Urca processes with nucleons (N-DURCA) and hyperons (Y-DURCA) are studied in the degenerate baryon matter of neutron stars. We investigate the effects of hyperon degrees of freedom and the Y-DURCA processes on the N-DURCA processes, and the total neutrino emissivity of neutron star matter. The results show that the existence of hyperons decreases the abundance of protons and leptons, and can sharply suppress the neutrino emissivity of the N-DURCA processes.
[1] Shapiro S L and Teukolsky S A 1983 Black Holes, White Dwarfs, and Neutron Stars: The Physics of Compact Objects (New York: A Wiley-Interscience Publication)
[2] Kaminker A D, Haensel P and Yakovlev D G 2001 Astron. Astrophys. 373 L17
[3] Gnedin O Y, Yakovlev D G and Shibanov Y A 1994 Astron. Lett. 20 409
[4] Levenfish K P, Shibanov Y A and Yakovlev D G 1998 Phys. Scripta T 77 79
[5] Yakovlev D G, Gnedin O Y, Kaminker A D and Potekhin A Y 2008 AIP Conf. Series 983 379
[6] Schaffner J and Mishustin I N 1996 Phys. Rev. C 53 1416
[7] Pal S, Hanauske M, Zakout I, Stöcker H and Greiner W 1999 Phys. Rev. C 60 015802
[8] Prakash M, Prakash M, Lattimer J M and Pethick C J 1992 Astrophys. J. 390 L77
[9] Haensel P and Gnedin O Y 1994 Astron. Astrophys. 290 458
[10] Yakovlev D G, Kaminker A D, Gnedin O Y and Haensel P 2001 Phys. Rep. 354 1
[11] Glendenning N K 1985 Astrophys. J. 293 470
[12] Glendenning N K and Moszkowski S A 1991 Phys. Rev. Lett. 67 2414
[13] Bednarek I and Manka R 2005 J. Phys. G: Nucl. Phys. 31 1009
[14] Batty C J, Friedman E and Gai A 1994 Phys. Lett. B 335 273
[15] Simon B 1983 Ann. Phys. 146 209
[16] Leinson L B and Pérez A 2001 Phys. Lett. B 518 15
[17] Takahashi H and Ahn J K 2001 Phys. Rev. Lett. 87 212502
[18] Yang F and Shen H 2008 Phys. Rev. C 77 025801
[19] Danysz M 1963 Nucl. Phys. 49 121
[20] Prowse D J 1966 Phys. Rev. Lett. 17 782
[21] Aoki S and Bahk S Y 1991 Prog. Theor. Phys. 85 1287
[22] Jones P B 2001 Phys. Rev. D 64 084003
[23] Jones P B 2001 Phys. Rev. Lett. 86 1384
[24] Pan N, Zheng X and Li J 2006 Mon. Not. Roy. Astron. Soc. 371 1359
[25] Reisenegger A 1995 Astrophys. J. 442 749
[26] Kang M and Zheng X 2007 Mon. Not. Roy. Astron. Soc. 375 1503
2011, Vol. 28 
