other query modes : |
Identifier query |
Coordinate query |
Criteria query |
Reference query |
Basic query |
Script submission |
TAP |
Output options |
Object types |
Help |
2002MNRAS.333..825C - Mon. Not. R. Astron. Soc., 333, 825-834 (2002/July-2)
Global metallicity of globular cluster stars from colour-magnitude diagrams.
CAPUTO F. and CASSISI S.
Abstract (from CDS):
Taking into account these predictions, we introduce a new observable based on the visual magnitude difference between the TO and the ZAHB [ΔMV(TO-ZAHB)], and the TO and the BUMP [ΔMV(TO-BUMP)], given by A=ΔMV(TO-BUMP)-0.566ΔMV(TO-ZAHB). We show that the parameter A does not depend at all on the cluster age, but that it does strongly depend on the cluster global metallicity. The calibration of the parameter A as a function of Z is then provided, as based on our evolutionary models. We tested the reliability of this result by also considering stellar models computed by other authors, employing different input physics. Eventually, we present clear evidence that the variation of ΔMV(TO-BUMP) with ΔMV(TO-ZAHB) does supply a powerful probe of the global metal abundance, at least when homogeneous theoretical frameworks are adopted. Specifically, we show that the extensive set of models by Vanden Berg et al. suggests a slightly different calibration of A versus Z calibration, which however provides global metallicities higher by only 0.08±0.06dex with respect to the results from our computations.
We provide an estimate of the global metallicity of 36 globular clusters in the Milky Way, based on our A -Z calibration, and a large observational data base of Galactic globular clusters. By considering the empirical [Fe/H] scales by both Zinn & West and Carretta & Gratton, we are able to provide an estimate of the α -element enhancement for all clusters in our sample. We show that the trend of [α/Fe] with respect to the iron content significantly depends on the adopted empirical [Fe/H] scale, with the Zinn & West one suggesting α -element enhancements in fine agreement with current spectroscopic measurements.
Abstract Copyright: 2002 Blackwell Science Ltd
Journal keyword(s): stars: evolution - globular clusters: general
Simbad objects: 36
To bookmark this query, right click on this link: simbad:2002MNRAS.333..825C and select 'bookmark this link' or equivalent in the popup menu