Ultra-compact X-ray binaries （UCXBs） are very interesting and impor- tant objects. By taking the population synthesis approach to the evolution of binaries, we carry out a detailed study of UCXBs. We estimate that t...Ultra-compact X-ray binaries （UCXBs） are very interesting and impor- tant objects. By taking the population synthesis approach to the evolution of binaries, we carry out a detailed study of UCXBs. We estimate that there are - 5000-10000 UCXBs in the Galaxy, and their birthrates are - 2.6-7.5×10-4 yr-1. Most UCXBs are transient X-ray sources, but their X-ray luminosities are much lower than those of persistent sources. Therefore, the majority of observed UCXBs should be persistent sources. About 40% - 70% of neutron stars （NSs） in UCXBs form via an accretion- induced collapse from an accreting ONe white dwarf （WD）, 1%-10% of NSs in UCXBs form via core-collapse supernovae and others form via the evolution-induced collapse of a naked helium star. About 50% - 80% of UCXBs have naked helium star donors, 5% - 10% of UCXBs have HeWD donors, 15% - 40% of UCXBs have COWD donors and UCXBs with ONeWD indicates that the uncertainty mainly comes which develops in these systems. donors are negligible. Our investigation from evolution of the common-envelope展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 11063002 and 11163005)the Natural Science Foundation of Xinjiang(Nos. 2009211B01 and 2010211B05)+2 种基金Foundation of Huo Yingdong (No. 121107)Foundation of Ministry of Education (No. 211198)Doctor Foundation of Xinjiang University (BS100106)
文摘Ultra-compact X-ray binaries （UCXBs） are very interesting and impor- tant objects. By taking the population synthesis approach to the evolution of binaries, we carry out a detailed study of UCXBs. We estimate that there are - 5000-10000 UCXBs in the Galaxy, and their birthrates are - 2.6-7.5×10-4 yr-1. Most UCXBs are transient X-ray sources, but their X-ray luminosities are much lower than those of persistent sources. Therefore, the majority of observed UCXBs should be persistent sources. About 40% - 70% of neutron stars （NSs） in UCXBs form via an accretion- induced collapse from an accreting ONe white dwarf （WD）, 1%-10% of NSs in UCXBs form via core-collapse supernovae and others form via the evolution-induced collapse of a naked helium star. About 50% - 80% of UCXBs have naked helium star donors, 5% - 10% of UCXBs have HeWD donors, 15% - 40% of UCXBs have COWD donors and UCXBs with ONeWD indicates that the uncertainty mainly comes which develops in these systems. donors are negligible. Our investigation from evolution of the common-envelope
