Speaker
Prof.
Timothy Beers
(University of Notre Dame)
Description
I report on the spatial distributions of carbonicity, [C/Fe], and
metallicity, [Fe/H], of the halo system of the Milky Way, based on
medium-resolution spectroscopy of ~58,000 stars in the Southern
Hemisphere from the AAOmega Evolution of Galactic Structure (AEGIS)
survey. I also consider the populations of carbon-enhanced metal-poor
(CEMP) stars present in the AEGIS sample and confirm that the
cumulative frequency of CEMP stars strongly increases with decreasing
metallicity, as seen previously. The differential frequency of CEMP-no
stars (as classified by their characteristically lower levels of
absolute carbon abundance) increases with decreasing metallicity, and is
substantially higher than previous determinations for CEMP stars as a
whole. In contrast, that of CEMP-s stars remains almost flat, at a value
~10%, in the range -4.0 < [Fe/H] < -2.0.
Primary author
Prof.
Timothy Beers
(University of Notre Dame)