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Register a new userDiagnosing the Stellar Population and Tidal Structure of the Blanco1 Star Cluster
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We present the stellar population, using {it Gaia},DR2 parallax, kinematics, and photometry, of the young ($sim 100$~Myr), nearby ($sim 230$~pc) open cluster, Blanco1. A total of 644 member candidates are identified via the unsupervised machine learning method textsc{StarGO} to find the clustering in the 5-dimensional position and proper motion parameter ($X$, $Y$, $Z$, $mu_alpha cosdelta$, $mu_delta$) space. Within the tidal radius of $10.0 pm 0.3$~pc, there are 488 member candidates, 3 times more than those outside. A leading tail and a trailing tail, each of 50--60~pc in the Galactic plane, are found for the first time for this cluster, with stars further from the cluster center streaming away faster, manifest stellar stripping. Blanco1 has a total detected mass of $285pm32$~M$_odot $ with a mass function consistent with a slope of $alpha=1.35pm0.2$ in the sense of $dN/dm propto m^{-alpha}$, in the mass range of 0.25--2.51~M$_odot $, where $N$ is the number of members and $m$ is stellar mass. A Minimum Spanning Tree ($Lambda_{rm MSR}$) analysis shows the cluster to be moderately mass segregated among the most massive members ($gtrsim 1.4$~M$_odot$), suggesting an early stage of dynamical disintegration.
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