Investigations on Proper Motion XVIII. The Proper Motions of TwentyOne Planetary Nebulae
Abstract
From photographs taken at the 80foot focus of the 60inch reflector proper motions were derived for fifteen more planetary nebulae, making a total of twentyone nebulae. The mean interval between the old and the new plates is 12.22 years; the probable error of the mean motions is 0.0009" in α and 0.0010" in δ The results for the absolute motions of all twentyone objects range from 0.0002" to 0.017", the mean being 0.007". The mean parallax derived from these results is about 0.0007", yielding an absolute photographic magnitude of +1.9 for the central stars and an absolute bolometric magnitude of 0.8
 Publication:

The Astrophysical Journal
 Pub Date:
 April 1933
 DOI:
 10.1086/143457
 Bibcode:
 1933ApJ....77..186V