The outer - halo globular cluster NGC 6229 III . Deep CCD
نویسنده
چکیده
Deep BV photometry for a large field covering the outer-halo globular cluster NGC 6229 is presented. For the first time, a colour-magnitude diagram (CMD) reaching below the main sequence turnoff has been obtained for this cluster. Previous results regarding the overall morphology of the horizontal and giant branches are confirmed. In addition, nine possible extreme horizontal-branch stars have been identified in our deep images, as well as thirty-three candidate blue stragglers. We also find the latter to be more centrally concentrated than subgiant branch stars covering the same range in V magnitude. A comparison of the cluster CMD with the M 5 (NGC 5904) ridgeline from Sandquist et al. (1996) reveals that: i) NGC 6229 and M 5 have essentially identical metallicities; ii) NGC 6229 and M 5 have the same ages within the errors in spite of their different horizontal-branch morphologies.
منابع مشابه
The outer - halo globular cluster NGC 6229 . III . Deep CCD photometry
Deep BV photometry for a large field covering the outer-halo globular cluster NGC 6229 is presented. For the first time, a colour-magnitude diagram (CMD) reaching below the main sequence turnoff has been obtained for this cluster. Previous results regarding the overall morphology of the horizontal and giant branches are confirmed. In addition, nine possible extreme horizontalbranch stars have b...
متن کاملUnveiling Palomar 2: the Most Obscure Globular Cluster in the Outer Halo
We present the first color-magnitude study for Palomar 2, a distant and heavily obscured globular cluster near the Galactic anticenter. Our (V, V − I) color-magnitude diagram (CMD), obtained with the UH8K camera at the CFHT, reaches V (lim) ≃ 24 and clearly shows the principal sequences of the cluster, though with substantial overall foreground absorption and differential reddening. The CMD mor...
متن کاملar X iv : a st ro - p h / 04 11 62 1 v 1 2 2 N ov 2 00 4 Outer Versus Inner Halo Globular Clusters : NGC 7492 Abundances 1
We have carried out a detailed abundance analysis for 21 elements in a sample of four RGB stars in the outer halo globular cluster NGC 7492 (RGC 25 kpc); we find [Fe/H] = −1.82 dex inferred from Fe I lines (−1.79 from Fe II) using high dispersion (R=λ/∆λ=35,000) spectra obtained with HIRES at the Keck Observatory. Most elements show no sign of star-to-star variation within our limited sample. W...
متن کاملTwo New Halo Debris Streams in the Sloan Digital Sky Survey
Using photometry from Data Release 10 of the northern footprint of the Sloan Digital Sky Survey, we detect two new stellar streams with lengths of between 25◦ and 50◦. The streams, which we designate Hermus and Hyllus, are at distances of between 15 and 23 kpc from the Sun and pass primarily through Hercules and Corona Borealis. Stars in the streams appear to be metal poor, with [Fe/H] ∼ −2.3, ...
متن کاملThe Age of Old Magellanic Cloud Clusters . I : NGC 2257
Deep CCD photometry down to V 24:5 is presented for the old globular cluster NGC 2257 in the Large Magellanic Cloud. The main results of this study can be summarized as follows: i) the Red Giant Branch (RGB) Bump has been detected at V = 18:70:1, and it is compatible with determination of this feature in Galactic Globular Clusters; ii) using the currently accepted methods of dating Globular Clu...
متن کامل