The extended Main-Sequence Turnoff of the Milky Way open cluster
  Collinder 347
  We made use of the Gaia DR2 archive to comprehensively study the Milky Way
open cluster Collinder 347, known until now as a very young object of solar
metal-content. However, the G versus G_BP-G_RP colour-magnitude diagram (CMD)
of bonafide probable cluster members, selected on the basis of individual
stellar proper motions, their spatial distribution and placement in the CMD,
reveals the existence of a Hyades-like age open cluster (log(t /yr) = 8.8) of
moderately metal-poor chemical content ([Fe/H] = -0.4 dex), with a present-day
mass of 3.3x10^3 Mo. The cluster exhibits an extended Main-Sequence turnoff
(eMSTO) of nearly 500 Myr, while that computed assuming Gaussian distributions
from photometric errors, stellar binarity, rotation and metallicity spread
yields an eMSTO of ~340 Myr. Such an age difference points to the existence
within the cluster of stellar populations with different ages.
