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Photometry of the Lower Main Sequences of Nearby Clusters

Published online by Cambridge University Press:  14 August 2015

A. R. Upgren
Affiliation:
Van Vleck Observatory, Wesleyan University, Middletown, Connecticut
E. W. Weis
Affiliation:
Van Vleck Observatory, Wesleyan University, Middletown, Connecticut

Extract

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Photoelectric photometry in BVRI colors has been obtained at the Kitt Peak National Observatory of many stars in the regions of the Hyades, Praesepe and Coma star clusters which had no previous photometry. The stars were limited mostly to the lower main sequence. Their range is approximately 0.6 to 1.5 (and to 1.7 in the Hyades) in B-V and 0.25 to 0.85 (and to 1.3 in the Hyades) in R-I. Their ranges correspond from mid G through early M in spectral class. The purpose of this project is to detect and examine the main sequences of the nearest open clusters. It continues the results reported earlier in this program for the Hyades cluster [Upgren (1974), Upgren and Weis (1977)] and extends them to include Praesepe and Coma as well, by means of the new sensitive gallium-arsenide photocells which permit fainter stars to be observed with moderate sized telescopes, especially in the R and I bands.

Type
August 28 Open Clusters
Copyright
Copyright © Reidel 1980 

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