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The Exciting Star of the Berkeley 59/Cepheus OB4 Complex and Other Chance Variable Star Discoveries

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Daniel J. Majaess
David G. Turner

Department of Astronomy and Physics, Saint Mary's University, Halifax, NS, B3H 3C3, Canada
and
Visiting Astronomer, Dominion Astrophysical Observatory, Herzberg Institute of Astrophysics, National Research Council of Canada.


David J. Lane

Department of Astronomy and Physics, Saint Mary's University, Halifax, NS, B3H 3C3, Canada
and
Abbey Ridge Observatory, Stillwater Lake, NS, Canada.


Kathleen E. Moncrieff

Department of Astronomy and Physics, Saint Mary's University, Halifax, NS, B3H 3C3, Canada

 

Presented at the 96th Spring Meeting of the AAVSO, June 29, 2007; received December 4, 2007; revised January 24, 2008; accepted January 25, 2008

 

 

Abstract
A study is presented regarding the nature of several variable stars sampled during a campaign of photometric monitoring from the Abbey Ridge Observatory: three eclipsing binaries, two semiregulars, a luminous Be star, and a star of uncertain classification. For one of the eclipsing systems, BD+66°1673, spectroscopic observations reveal it to be an O5 V((f))n star and the probable ionizing star of the Berkeley 59/Cep OB4 complex. An analysis of spectroscopic observations and BV photometry for Berkeley 59 members in conjunction with published observations imply a cluster age of ~2 Myr, a distance of d = 883 +/-43 pc, and a reddening of E B-V = 1.38 +/-0.02. Two of the eclipsing systems are Algol-type, but one appears to be a cataclysmic variable associated with an X-ray source. ALS 10588, a B3 IVn star associated with the Cepheid SV Vul, is of uncertain classification, although consideration is given to it being a slowly pulsating B star. The environmental context of the variables is examined using spectroscopic parallax, 2MASS photometry, and proper motion data, the latter to evaluate the membership of the variable B2 Iabe star HDE 229059 in Berkeley 87, an open cluster that could offer a unique opportunity to constrain empirically the evolutionary lineage of young massive stars. Also presented are our null results for observations of a sample of northern stars listed as Cepheid candidates in the New Catalogue of Suspected Variable Stars (NSV, in Samus et al. 2004).

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