Calcium and light-elements abundance variations from high resolution spectroscopy in globular clusters

Details Calcium and light-elements abundance variations from high resolution spectroscopy in globular clusters Calcium and light-elements abundance variations from high resolution spectroscopy in globular clusters

2010-01-29

arxiv.org/abs/1002.0002v1

Astronomy and Astrophysics

Astrophysics

Galaxy Astrophysics

Uses emulateapj, 3 figures, 2 tables (1 only available in electronic form), accepted for publication on ApJ Letters

Scientific paper

We use abundances of Ca, O, Na, Al from high resolution UVES spectra of 200 red giants in 17 globular clusters (GCs) to investigate the correlation found by Lee et al. (2009) between chemical enrichment from SN II and star-to-star variations in light elements in GC stars. We find that (i) the [Ca/H] variations between first and second generation stars are tiny in most GCs (~0.02-0.03 dex, comparable with typical observational errors). In addition, (ii) using a large sample of red giants in M 4 with abundances from UVES spectra from Marino et al. (2008), we find that Ca and Fe abundances in the two populations of Na-poor and Na-rich stars are identical. These facts suggest that the separation seen in color-magnitude diagrams using the U band or hk index (as observed in NGC 1851 by Han et al. 2009) are not due to Ca variations. Small differences in [Ca/H] as associated to hk variations might be due to a small systematic effect in abundance analysis, because most O-poor/Na-rich (He-rich) stars have slightly larger [Fe/H] (by 0.027 dex on average, due to decreased H in the ratio) than first generation stars and are then located at redder positions in the V,hk plane. While a few GCs (M 54, omega Cen, M 22, maybe even NGC 1851) do actually show various degree of metallicity spread, our findings eliminate the need of a close link between the enrichment by core-collapse SNe with the mechanism responsible for the Na-O anticorrelation.

Affiliated with

Also associated with

No associations

Rating

Calcium and light-elements abundance variations from high resolution spectroscopy in globular clusters does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Calcium and light-elements abundance variations from high resolution spectroscopy in globular clusters, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Calcium and light-elements abundance variations from high resolution spectroscopy in globular clusters will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-251159