Deriving Definitive Parameters for the Long Period Cepheid S Vulpeculae (Abstract)

Volume 41 number 2 (2013)

David G. Turner

Saint Mary's University, Halifax, NS B3h 3C3, Canada; turner@ap.smu.ca

Abstract

(Abstract only) The long-period variable S Vul is now recognized to be a classical Cepheid, following a period a century ago when its status was less well established. Its pulsation period of 68.5 days makes S Vul the longest period Cepheid recognized in the Galaxy. Possible membership in an OB association was considered briefly thirty years ago, until it was discovered to be surrounded by a sparse cluster of faint stars designated as Turner 1. Membership of S Vul in the cluster was considered unlikely in the original photometric study of Turner 1 because of contradictory implications regarding the reddening and distance of S Vul with that of cluster stars, but a recent revisiting of the data supplemented by APASS observations indicates that the cluster and Cepheid are indeed related. The implications for the implied parameters of S Vul, its reddening, distance, age, and evolutionary mass, are discussed in light of our refined knowledge of the cluster in which the Cepheid resides.