论文标题
在球状簇中没有共生星
On the absence of symbiotic stars in globular clusters
论文作者
论文摘要
即使在银河场和附近星系中发现了许多共生星（Systs），但在银河球簇（GC）中尚未得到任何一个。我们首次通过分析具有不同初始特性的144个GC模型来研究GC中缺乏此类系统，该模型大致代表了银河GC种群。我们在这里专注于通过风能通道形成的系统，可以在二元种群合成代码中始终建模。我们发现，大多数此类系统的轨道周期足够长（$ {\ gtrsim10^3} $ d），因此，对于非常密集的GC模型，动态互动在销毁其祖细胞之前起着重要作用（$ {\ sim11-12} $ gyr）。在不太密集的GC模型中，仍然可以预测某些系统存在。但是，这些系统往往远离中央部分（$ {\ gtrsim70} $％远远超过半光差的半径），并且足够罕见（$ {\ {\ liseSim1} $每MMYR每MYR），这在观测活动中的识别很困难。我们建议在附近的低密度GC郊区进行GC中的Systs搜索，其中半质量松弛时间和相对较大的半乳酸距离。最后，我们获得了$ω$ CEN（SOPS IV E-94）提出的候选者的光谱，并表明该对象很可能不是Syst。
Even though plenty of symbiotic stars (SySts) have been found in the Galactic field and nearby galaxies, not a single one has ever been confirmed in a Galactic globular cluster (GC). We investigate the lack of such systems in GCs for the first time by analysing 144 GC models evolved with the MOCCA code, which have different initial properties and are roughly representative of the Galactic GC population. We focus here on SySts formed through the wind-accretion channel, which can be consistently modelled in binary population synthesis codes. We found that the orbital periods of the majority of such SySts are sufficiently long (${\gtrsim10^3}$ d) so that, for very dense GC models, dynamical interactions play an important role in destroying their progenitors before the present day (${\sim11-12}$ Gyr). In less dense GC models, some SySts are still predicted to exist. However, these systems tend to be located far from the central parts (${\gtrsim70}$ per cent are far beyond the half-light radius) and are sufficiently rare (${\lesssim1}$ per GC per Myr), which makes their identification rather difficult in observational campaigns. We propose that future searches for SySts in GCs should be performed in the outskirts of nearby low-density GCs with sufficiently long half-mass relaxation times and relatively large Galactocentric distances. Finally, we obtained spectra of the candidate proposed in $ω$ Cen (SOPS IV e-94) and showed that this object is most likely not a SySt.
