K-Band Red Clump Distances to the LMC Clusters Hodge 4 and NGC 1651
We present near-infrared color-magnitude diagrams for the LMC star clusters Hodge 4 and NGC 1651 revealing the helium burning red clump stars for the first time in the JK passbands. From these diagrams, which extend to K~19, and existing optical CMDs that reveal the clusters' main sequence turn...
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Zusammenfassung: | We present near-infrared color-magnitude diagrams for the LMC star clusters
Hodge 4 and NGC 1651 revealing the helium burning red clump stars for the first
time in the JK passbands. From these diagrams, which extend to K~19, and
existing optical CMDs that reveal the clusters' main sequence turnoffs, we
determine the following cluster parameters. For Hodge 4, we estimate a
metallicity of [Fe/H] = -0.17 +/- 0.04, an age of 1.7 +/- 0.3 Gyr, and a red
clump absolute magnitude of Mk(RC) = -1.64 +/- 0.17. Along with an adopted
reddening of E(J-K) = 0.03 +/- 0.01 based on the Burstein & Heiles and Schlegel
et al. reddening maps, we find a distance of (m-M)o = 18.52 +/- 0.17 for Hodge
4. In the case of NGC 1651, we derive [Fe/H] = -0.07 +/- 0.10, an age of 1.8
+/- 0.3 Gyr, Mk(RC) = -1.56 +/- 0.12, E(J-K) = 0.06 +/- 0.01, and (m-M)o =18.55
+/- 0.12, all measured in the same manner as for Hodge 4. Based on these two
clusters, we calculate a mean LMC distance of (m-M)o = 18.54 +/- 0.10. |
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DOI: | 10.48550/arxiv.astro-ph/0207588 |