The Nearby, Young, Chi1 Fornacis Cluster: Membership, Age, and an
  Extraordinary Ensemble of Dusty Debris Disks
  Only four star clusters are known within ~100 pc of Earth. Of these, the Chi1
For cluster has barely been studied. We use the Gaia DR2 catalog and other
published data to establish the cluster membership, structure, and age. The age
of and distance to the cluster are ~40 Myr and 104 pc, respectively. A
remarkable, unprecedented, aspect of the cluster is the large percentage of
M-type stars with warm excess infrared emission due to orbiting dust grains --
these stars lie in an annulus that straddles the tidal radius of the cluster.
The Chi1 For cluster appears to be closely related to two extensive, previously
known, groups of co-moving, coeval stars (the Tucana-Horologium and Columba
Associations) that are spread over much of the southern sky. While Tuc-Hor and
Chi1 For are comoving and coeval, the difference in the frequency of their warm
dusty debris disks at M-type stars could hardly be more dramatic.
