论文标题
年轻的银河集群NGC 225：二进制恒星含量和总质量估计
The young Galactic cluster NGC 225: binary stars content and total mass estimate
论文作者
论文摘要
已知银河恒星簇具有大量的二进制恒星，但是它们在整个集群的动态演化中的作用尚不全面地理解。 We investigated the influence of binary stars on the total mass estimate for the case of the moderately populated Galactic star cluster NGC 225. The analysis of multi-epoch radial velocities of the 29 brightest cluster members, obtained over two observational campaigns, in 1990-1991 and in 2019-2020, yields a value of binary fraction of $α=0.52$ (15 stars out of 29).使用理论等时线和蒙特卡洛模拟，我们发现当正确考虑二进制文件时，簇质量至少增加了1.23倍。通过将GAIA EDR3光度数据与我们的光谱观测相结合，我们得出了NGC 225基本参数的估计，如下所示：平均径向速度$ <V_R> = -9.8 \ pm 0.7 $ 0.7 $ km S $ s $ $ e（b-v）= 0.29 \ pm 0.01 $ mag。
Galactic star clusters are known to harbour a significant amount of binary stars, yet their role in the dynamical evolution of the cluster as a whole is not comprehensively understood. We investigated the influence of binary stars on the total mass estimate for the case of the moderately populated Galactic star cluster NGC 225. The analysis of multi-epoch radial velocities of the 29 brightest cluster members, obtained over two observational campaigns, in 1990-1991 and in 2019-2020, yields a value of binary fraction of $α=0.52$ (15 stars out of 29). Using theoretical isochrones and Monte Carlo simulations we found that the cluster mass increases at least 1.23 times when binaries are properly taken into account. By combining Gaia EDR3 photometric data with our spectroscopic observations, we derived estimates of NGC 225 fundamental parameters as follows: mean radial velocity $<V_r> = -9.8 \pm 0.7$ km s$^{-1}$, $\log(τ)$=8.0-8.2 dex, distance $ D = 676 \pm 22$ pc, and colour excess $E(B-V) = 0.29 \pm 0.01$ mag.
