Galactic planetary nebulae and their central stars^*

II. Proper motions

¹ ESO, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany e-mail: [fkerber;awicenec]@eso.org
² Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking – Surrey, RH5 6NT, UK e-mail: rm2@mssl.ucl.ac.uk
³ INAF, Osservatorio Astronomico di Torino, via Osservatorio 20, 10025 Pino Torinese, Italy e-mail: smart@oato.inaf.it

Received: 2 July 2007
Accepted: 29 November 2007

Abstract

Context.More than 1500 Galactic planetary nebulae (PNe) are known but only a tiny fraction of them have measured proper motions. To date, the largest set of proper motion (PM) data for PNe is the one by Cudworth (1974), which includes 62 objects 25 of which have PM with significance better than 3σ in at least one component.

Aims.With our new compilation of 234 PNe we enlarge – compared to Cudworth's 25 – by almost an order of magnitude the number of PNe and central stars (CSs) with reliably measured proper motion (i.e. with significance better than 3σ in at least one component) and confirm some previous measurements.

Methods.We have used all-sky astrometric catalogues available via the Vizier database to collect proper motion information for a sample of objects selected from the catalogue of PNe positions of Kerber et al. (2003a, A&A, 408, 1029).

Results.We have derived proper motion information for a total of 234 PNe (274 when including 40 doubtful candidates). We include all PNe for which a confidence level of at least 3σ was achieved in at least one proper motion component. For many objects PM data are available from more than one catalogue and agreement between different catalogues is usually very reasonable providing independent confirmation of the results. For comparison with Cudworth's results we use the proper motion modulus as a metric. We cross-correlated his 62 objects with our master catalogue and found 12 matching objects out of the 18 with > in his list. For these we find good agreement for 10 out of the 12 objects, while we find significant PM for another five objects with PM reported by Cudworth. The number of objects we have in common was limited by several factors discussed in the paper.

Conclusions.With 234 (274 including doubtful candidates) entries our work is the largest available compilation of proper motion data for PNe and their CSs. This compilation opens new opportunities for studies of orbital kinematics of PNe in the Galaxy.