Showing papers by "H. Bruntt published in 1999"
TL;DR: Stromgren photometry of the two southern open clusters NGC 6134 and NGC 3680 is presented in this article, where the Stromgren indices are used to measure metallicity and interstellar reddening of the clusters.
Abstract: We present Stromgren photometry of the two southern open clusters NGC 6134 and NGC 3680. The eld of NGC 6134 was observed with dierent shifts of the telescope and rotations of the CCD camera in order to detect and remove any large scale flat eld errors us- ing the technique described by Andersen et al. (1995). By using calibrations of the Stromgren indices we nd the metallicity and interstellar reddening of the clusters: For NGC 6134 the results are (Fe/H) = 0:28 0:02 and E(b y )=0 :263 0:004 and for NGC 3680 we nd (Fe=H) = 0:09 0:02 and E(b y )=0 :048 0:011. When comparing the observed colour-magnitude diagrams theo- retical isochrones we nd that models which include over- shooting in the convective cores agree with the extended hook after the turno. From the isochrone t we nd ages of 0:69 0:10 Gyr and 1:45 0:15 Gyr for NGC 6134 and NGC 3680 respectively. Stromgren photometry of six known Scuti stars in NGC 6134 is presented.
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