Globular Cluster Ages and Distances
نویسندگان
چکیده
منابع مشابه
Globular cluster ages.
We review two new methods to determine the age of globular clusters (GCs). These two methods are more accurate than the classical isochrone fitting technique. The first method is based on the morphology of the horizontal branch and is independent of the distance modulus of the globular cluster. The second method uses a careful binning of the stellar luminosity function and determines simultaneo...
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Strömgren uvby CCD photometry can be used in a variety of ways to constrain the absolute and relative ages of globular clusters. The reddening corrected v−y, c1 diagram offers the means to derive ages that are completely independent of distance. Very precise differential ages for clusters of the same chemical composition may also be determined from such 2–color plots, or from measurements of th...
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We review the results on distances and absolute ages of galactic globular clusters (GCs) obtained after the release of the Hipparcos catalogue. Several methods aimed at the definition of the Population II local distance scale are discussed, and their results compared. We notice that while some methods yield distances to the center of the LMC (identified here with the bar), other give distances ...
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Main sequence turno magnitudes from the recent set of Yale isochrones (Chaboyer et al. 1995) have been combined with a variety of relations for the absolute magnitude of RR Lyr stars (Mv(RR)) to calibrate age as a function of the di erence in magnitude between the main sequence turn-o and the horizontal branch ( V HB). A best estimate for the calibration of Mv(RR) is derived from a survey of th...
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We present distance modulus and reddening determinations for 72 Galactic globular clusters from the homogeneous photometric database of Piotto et al. (2002), calibrated to the HST flight F439W and F555W bands. The distances have been determined by comparison with theoretical absolute magnitudes of the ZAHB. For low and intermediate metallicity clusters, we have estimated the apparent Zero Age H...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1980
ISSN: 0074-1809
DOI: 10.1017/s0074180900092081