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Open cluster NGC 2158

Journal Article · · Astrophys. J.; (United States)
DOI:https://doi.org/10.1086/163734· OSTI ID:5446266
CCD photometry on the BV system is presented for the intermediate-age open cluster NGC 2158. A new color-magnitude diagram for the cluster is derived which extends well down onto the main sequence. Using estimates for the cluster metallicity and reddening from the literature and new values derived from low-resolution IIDS spectra of several cluster giants, an age is obtained for NGC 2158 of 3.0 + or - 1.0 Gyr and an apparent distance modulus of 14.4. In comparison to NGC 2420, an open cluster also located in the anticenter but further from the Galactic plane, NGC 2158 is slightly younger and more metal-poor. The globular cluster 47 Tucanae and NGC 2420 have been thought to have the same metallicity, a conclusion that has led to considerable discussion of the differences in the color-magnitude diagrams of these two clusters. In contrast, evidence is found that NGC 2158 and 47 Tuc are more similar in metallicity. NGC 2158 is also similar in age and composition to the type VI clusters seen in the Large Magellanic Cloud. A comparison of NGC 2158 with NGC 1978 in the LMC leads to a distance modulus of 18.2 for the LMC. 37 references.
Research Organization:
Hawaii Univ., Honolulu; Canada-France-Hawaii Telescope Corp., Kamuela, HI; Boston Univ., MA
OSTI ID:
5446266
Journal Information:
Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 299; ISSN ASJOA
Country of Publication:
United States
Language:
English