Nine new open clusters within 500pc from the Sun

This under-density may be due to an ineffectiveness in the detection of larger structures with lower surface brightness. We report on our attempts to reveal such clusters.

We derived proper motions from a combination of Tycho-2 with URAT1, and obtained a mean precision of about 1.4mas/yr per co-ordinate for 1.3 million stars north of -20{deg} declination. We cut the sky into narrow proper motion slices and searched for spatial over-densities of stars in each slice. We then examined stars from over-densities in optical and near-infrared colour-magnitude diagrams to determine if they are compatible with isochrones of a cluster.