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Paper: CCD-photometry of open clusters containing Cepheid variables - NGC 7790
Volume: 4, The Extragalactic Distance Scale: Proceedings of the ASP 100th Anniversary Symposium
Page: 176
Authors: Romeo, G.; Fusi Pecci, F.; Bonifazi, A.; Tosi, M.
Abstract: New BVRI CCD photometry of the cluster NGC 7790 is presented. A main sequence ridge line corresponding to the blue envelope shifted toward the red by a quantity comparable to the size of the photometric error in B-V and V-I is defined. The resulting color-magnitude diagrams are used to derive new and accurate estimates of the reddening and distance modulus of the cluster: E(B-V) = 0.54 + or - 0.04 and (m-M)0 = 12.65 + or - 0.15. The absolute magnitudes of three Cepheids corresponding to these values are used to compute the zero points of the period-luminosity and period-luminosity-color relations, which are given. The obtained parameter are used together with assumed solar compositions to obtain the age of NGC 7790 at (5.0 + or - 1.5) x 10 to the 7th yr using 'standard' models or (1.0 + or - 0.2) x 10 to the 8th yr adopting models with overshooting.
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