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Field Stars , Open Clusters , and the Galactic Abundance Gradient
| Content Provider | Semantic Scholar |
|---|---|
| Author | Corder, Stuartt A. Twarog, Bruce A. |
| Copyright Year | 2001 |
| Abstract | The effects of the orbital diffusion of stars and clusters on the galactic abundance gradient have been modelled. For a single generation of field stars, the results confirm previous analyses based upon the assumption of a linear gradient with galactocentric distance. Though the dispersion in metallicity at a given radius grows with time, the underlying slope across the disk remains unchanged. For a disk dominated by a discontinuity in [Fe/H] beyond the solar circle, but no gradient within the inner or outer disk, a gradient is derived for any sample whose galactocentric baseline overlaps the discontinuity. The narrower the range in distance around the discontinuity, the steeper the gradient. The consequence of orbital diffusion is to shift the observable edge of the transition in [Fe/H] toward smaller galactocentric distance, enhancing the detection of a gradient. In contrast, star clusters of a single generation evaporate so quickly that the small surviving sample of the oldest clusters is statistically incapable of defining any gradient except a linear case. Inclusion of multiple generations of stars and clusters with a plausible age-metallicity relation enhances these patterns by expanding the metallicity range at a given galactocentric distance through the inclusion of stars with a wide range in both age and galactocentric origin. For field stars, the metallicity distribution of stars in the solar neighborhood is virtually indistinguishable for the two cases modelled. Because ages, abundances, and distances can be reliably determined for clusters and any sample of clusters is invariably dominated by those clusters formed over the last 2 Gyrs, the cluster population offers a viable means for finding detailed structure within the recent galactic abundance gradient. Using clusters to extend the galactocentric baseline would supply an additional critical test of the discontinuity. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://arxiv.org/pdf/astro-ph/0106136v1.pdf |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | ABRA gene Baseline (configuration management) Computer cluster Distance Evaporation Field electron emission GUCY2C protein, human Gradient Iron Molecular orbital Observable Reflections of signals on conducting lines Small Stars, Celestial |
| Content Type | Text |
| Resource Type | Article |
