Absolute proper motion of the Galactic open cluster M 67

Abstract

We derived the absolute proper motion (PM) of the old, solar-metallicity Galactic open cluster M 67 using observations collected with CFHT (1997) and with LBT (2007). About 50 galaxies with relatively sharp nuclei allow us to determine the absolute PM of the cluster. We find (μα cos δ, μα)J2000.0 = (.9.6 ± 1.1,.3.7 ± 0.8) mas yr.1. By adopting a line-of-sight velocity of 33.78 ±± 0.18 km s.1, and assuming a distance of 815 ± 50 pc, we explore the influence of the Galactic potential, with and without the bar and/or spiral arms, on the galactic orbit of the cluster. © 2010 ESO.