Browsing by Author "Escobar, M. E."

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    Erratum: "The Globular Cluster NGC 5286. II. Variable Stars" (2010, AJ, 139, 357)
    (2010) Zorotovic, M.; Catelan, Márcio; Smith, H. A.; Pritzl, B. J.; Aguirre, P.; Angulo, R. E.; Aravena, M.; Assef, R. J.; Contreras, C.; Cortés, C.; De Martini, G.; Escobar, M. E.; González, D.; Jofré, P.; Lacerna, I.; Navarro, C.; Palma, O.; Prieto, G. E.; Recabarren, E.; Triviño, J.; Vidal, E.
    The Fourier decomposition program used in our paper contained a small error that affected the calculation of the temperatures as well as the V - I colors inferred for the RRab stars. The temperatures that appear in Table 6 in the published article are slightly overestimated, and the V - I colors underestimated. A corrected version of Table 6 is presented below....
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    The globular cluster M 69: color-magnitude diagram and variable stars
    (2010) Escobar, M. E.; Catelan, Marcio; Zoccali, M.; Smith, H. A.; Pritzl, B. J.; Layden, A.; Gregorsok, J.; Welch, D. L.; Webb, T.
    We present BV photometry and the results of a search for stellar variability in the Galactic globular cluster M 69. The resulting color-magnitude diagram shows significant contamination by field stars. In our variability search we found 62 variable stars, 54 of which were new discoveries....
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    THE GLOBULAR CLUSTER NGC 5286. I. A NEW CCD BV COLOR-MAGNITUDE DIAGRAM
    (2009) Zorotovic, M.; Catelan, M.; Zoccali, M.; Pritzl, B. J.; Smith, H. A.; Stephens, A. W.; Contreras, R.; Escobar, M. E.
    We present BV photometry of the Galactic globular cluster NGC 5286, based on 128 V frames and 133 B frames, and covering the entire face of the cluster. Our photometry reaches almost two magnitudes below the turn-off level, and is accordingly suitable for age analysis. Field stars were removed statistically from the cluster's color-magnitude diagram (CMD), and a differential reddening correction applied, thus allowing a precise ridgeline to be calculated. Using the latter, a metallicity of [Fe/H] = - 1.70 +/- 0.05 in the Zinn & West scale, and [Fe/H] = - 1.47 +/- 0.02 in the Carretta & Gratton scale, was derived on the basis of several parameters measured from the red giant branch, in good agreement with the value provided in the Harris catalog. Comparing the NGC 5286 CMD with the latest photometry for M3 by P. B. Stetson, and using VandenBerg isochrones for a suitable chemical composition, we find evidence that NGC 5286 is around 1.7 +/- 0.9 Gyr older than M3. This goes in the right sense to help account for the blue horizontal branch of NGC 5286, for which we provide a measurement of several morphological indicators. If NGC 5286 is a bona fide member of the Canis Major dwarf spheroidal galaxy, as previously suggested, our results imply that the latter's oldest components may be at least as old as the oldest Milky Way globular clusters.