银河系甚弱X射线暂现源的研究进展  

Review of Galactic Very Faint X-ray Transients

作　　者：刘佰生 李向东[1,2] 

机构地区：[1]南京大学天文与空间科学学院,南京210023 [2]现代天文与天体物理重点实验室(南京大学),南京210023

出　　处：《天文学进展》2017年第2期190-207,共18页Progress In Astronomy

基　　金：国家自然科学基金(11133001;11133004)

摘　　要：银河系内的X射线双星暂现源大多是吸积的黑洞或中子星系统。最近十几年以来,还探测到几十颗具有极低爆发光度(2～10 keV的光度约10^(27)～10^(29) J·s^(-1))的X射线暂现源,称为甚弱X射线暂现源(very faint X-ray transient,简称VFXT)。根据观测和理论分析,VFXT的长期平均物质吸积率约小于10^(-13)～10^(-12) M_⊙·a^(-1),这样低的吸积率无法用传统的X射线双星演化理论解释。首先总结了VFXT的观测特征,指出其族群多样性的特征。评述了现有可能的机制,并指出还需要更多的观测和理论研究来揭示这类奇特的暂现源的本质。Most transient X-ray binaries(XRBs) in our Galaxy contain accreting black holes or neutron stars. In last twenty years, a new type of X-ray transients, which display very low outburst luminosity(2～10 keV luminosity of approximate 10^(27)～10^(29)J·s^(-1)), have been detected and termed as very faint X-ray transients(VFXTs). According to current observations and theoretical studies, the long-term averaged mass accretion rate in VFXTs is 10^(-13)～10^(-12)M_⊙·a^(-1). Such a low accretion rate can hardly been explained by traditional XRB evolution theory. In this paper we review the observational properties of VFXTs and candidates, including their space distribution, X-ray radiation, companion stars and orbital period distribution. We then summarize the theoretical models for the origin of VFXTs proposed in the literature and discuss their feasibility. It is pointed out that more observations and theoretical studies are needed to illustrate the nature of these exotic objects.

关 键 词：吸积 吸积盘 白矮星 中子星 X射线双星 恒星演化 

分 类 号：P142.3[天文地球—天体物理] P153[天文地球—天文学]