Evidence of Early-stage Tidal Structures of Open Clusters Revealed by
  Kinematics with Gaia EDR3
  Blanco 1, a 100Myr open cluster in the solar neighborhood, is well known for
its two 50pc-long tidal tails. Taking Blanco 1 as a reference, we find evidence
of early-stage tidal disruption in two other open clusters of ~120Myr: the
Pleiades and NGC 2516, via Gaia EDR3 data. These two clusters have a total mass
of 2-6 times that of Blanco 1. Despite having a similar age as Blanco 1, the
Pleiades and NGC 2516 have a larger fraction of their members bound: 86% of
their mass is inside the tidal radius, versus 63% for Blanco 1. However, a
correlation between Blanco 1's 50pc-long tidal tails and the "kinematic tails"
in velocity space is also found for the Pleiades and NGC 2516. This evidence
supports the idea that the modest elongation seen in the spatial distribution
for the Pleiades and NGC 2516 is a result of early-stage tidal disruption.
