Astronomy and Astrophysics – Astronomy
Scientific paper
Dec 2007
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007aas...21110418k&link_type=abstract
American Astronomical Society, AAS Meeting #211, #104.18; Bulletin of the American Astronomical Society, Vol. 39, p.927
Astronomy and Astrophysics
Astronomy
Scientific paper
In the hierarchical model of galaxy formation, the Milky Way (MW) halo is thought to have been built up from its dwarf satellites. However, the stars in the most metal-poor class of MW satellites, the dwarf spheroidals (dSphs), exhibit two chemical abundance discrepancies compared to stars in the halo: lower alpha element (e.g., Ca, Ti, Si) to iron ratios [α/Fe] and the apparent absence of extremely metal-poor stars. The disparities suggest that the stellar populations of the surviving dSphs evolved differently from the disrupted dSphs that formed the halo. Exploring the chemical assembly of the halo would benefit from abundance measurements in a large sample of stars in a variety of systems ranging from compact dSphs to the diffuse halo. However, few halo and dSph stars are bright enough for high resolution spectroscopy, the standard tool of detailed abundance analysis. We present a technique to determine [Fe/H] and [α/Fe] from individual iron and alpha element lines in medium resolution spectra from the DEIMOS spectrometer (R 6000) on the Keck II telescope. The moderate dispersion and multiplexing drastically increase the accessibility of halo and dSph stars not only in the MW, but also M31. Using a grid of spectral syntheses of stellar atmospheres in local thermodynamic equilibrium, we have measured iron abundances from the neutral iron lines in DEIMOS spectra of individual red giants in well-studied MW globular clusters and the Leo I dSph. The abundances are consistent with high resolution studies over a wide range of [Fe/H].
This work is supported by NSF grants AST-0607852 and AST-0607708.
Guhathakurta Puraga
Kirby Evan
Sneden Chistopher
No associations
LandOfFree
Iron and Alpha from Medium Resolution Spectra of Individual Stars 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 Iron and Alpha from Medium Resolution Spectra of Individual Stars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Iron and Alpha from Medium Resolution Spectra of Individual Stars will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1480724