Galactic clusters with associated Cepheid variables – VII. Berkeley 58 and CG Cassiopeiae |
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| Authors: | D G Turner †‡§ D Forbes † D English ‡ P J T Leonard J N Scrimger A W Wehlau R L Phelps † L N Berdnikov § E N Pastukhova |
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| Institution: | Department of Astronomy and Physics, Saint Mary's University, Halifax, Nova Scotia B3H 3C3, Canada;Department of Physics, Sir Wilfred Grenfell College, Memorial University of Newfoundland, Corner Brook, NF A2H 6P9, Canada;ADNET Systems, Inc., 7515 Mission Dr, Suite A1C1, Lanham, Maryland 20706, USA;Faculty of Computer Science, Dalhousie University, Halifax, Nova Scotia B3H 1W5, Canada;Department of Physics and Astronomy, The University of Western Ontario, London, Ontario N6A 3K7, Canada;Office of Integrative Activities, National Science Foundation, Division of Astronomical Sciences, 4201 Wilson Blvd, Arlington, Virginia 22230, USA;Sternberg Astronomical Institute, 13 Universitetskij prosp., Moscow 119992, Russia;Institute of Astronomy, Russian Academy of Sciences, 48 Pyatnitskaya ul, Moscow 109017, Russia |
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| Abstract: | Photoelectric, photographic and CCD UBV photometry, spectroscopic observations and star counts are presented for the open cluster Berkeley 58 to examine a possible association with the 4.37 d Cepheid CG Cas. The cluster is difficult to separate from the early-type stars belonging to the Perseus spiral arm, in which it is located, but has reasonably well-defined parameters: an evolutionary age of ～108 yr, a mean reddening of E ( B ? V ) (B0) = 0.70 ± 0.03 s.e. and a distance of 3.03 ± 0.17 kpc ( V 0? M V = 12.40 ± 0.12 s.d.). CG Cas is a likely cluster coronal member on the basis of radial velocity, and its period increase of +0.170 ± 0.014 s yr?1 and large light amplitude describe a Cepheid in the third crossing of the instability strip lying slightly blueward of strip centre. Its inferred reddening and luminosity are E ( B ? V ) = 0.64 ± 0.02 s.e. and 〈 M V 〉=?3.06 ± 0.12 . A possible K supergiant may also be a cluster member. |
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| Keywords: | stars: evolution Cepheids open clusters and associations: individual: Berkeley 58 |
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