Characteristics of the Variable Star P Cygni Determined From Cluster Membership
Volume 29 number 2 (2001)
- David G. Turner
- Saint Mary’s University Halifax, Nova Scotia, B3H 3C3 Canada
- Gary Welch
- Saint Mary’s University Halifax, Nova Scotia, B3H 3C3 Canada
- Marianne Graham
- Saint Mary’s University Halifax, Nova Scotia, B3H 3C3 Canada
- David Fairweather
- Saint Mary’s University Halifax, Nova Scotia, B3H 3C3 Canada
- Andrew Horsford
- Typex Business Centre Newcastle-Upon-Tyne United Kingdom
- Michael Seymour
- Queen’s University Kingston, Ontario, K7L 3N6 Canada
- Walter Feibelman
- Goddard Space Flight Center Laboratory for Astronomy and Solar Physics Code 681 Greenbelt, MD 20771
Abstract
Empirical information on the luminosity, reddening, age, and mass of the variable B2 Oe supergiant P Cygni is derived from its assumed membership in the sparse anonymous cluster on which it is projected, as well as its association with the spatially adjacent cluster IC 4996, which forms a double cluster with the P Cyg cluster. Evidence for the high luminosity of P Cyg is confirmed by its derived absolute magnitude of M(v) = -8.46 +/-0.03, which translates to log (L/L(solar)) = 5.54 +/-0.02 for an effective temperature consistent with the star's derived space reddening (E(B-V)=0.53 +/-0.02). More surprising is an age for the associated clusters of 6 (+/-1.5) x 10^6 years, corresponding to a turnoff point mass of 25.1 (+/-5.5 solar mass). By inference, P Cygni, as a post main-sequence object, should have a mass of no more than ~23-25 solar mass.