Three new Galactic star clusters discovered in the field of the open
  cluster NGC 5999 with Gaia DR2
  We report the serendipitous discovery of three new open clusters, named UFMG
1, UFMG 2 and UFMG 3 in the field of the intermediate-age cluster NGC 5999, by
using Gaia DR2 data. A colour-magnitude filter tailored for a proper selection
of main-sequence stars and red clump giants turned evident the presence of NGC
5999 and these three new stellar groups in proper motion space. Their
structural parameters were derived from King-profile fittings over their
projected stellar distributions and isochrone fits were performed on the
clusters cleaned colour-magnitude diagrams built with Gaia bands to derive
their astrophysical parameters. The clusters projected sky motion were
calculated for each target using our members selection. Distances to the
clusters were inferred from stellar parallaxes through a bayesian model,
showing that they are marginally consistent with their isochronal distances,
considering the random and systematic uncertainties involved. The new clusters
are located in the nearby Sagittarius arm (d ~ 1.5 kpc) with NGC 5999 at the
background (d ~ 1.8 kpc). They contain at least a few hundred stars of nearly
solar metallicity and have ages between 100 and 1400 Myr.
