The Search for Extremely Low-Metallicity Stars in Dwarf Galaxies Using the NIR Ca II Triplet

Starkenburg, E.; Hill, V.; Tolstoy, E.; González Hernández, J. I.; Irwin, M.; Helmi, A.; Boschman, L.; Francois, P.; Battaglia, G.; Jablonka, P.; Tafelmeyer, M.; Shetrone, M.; Venn, K.; de Boer, T.
Referencia bibliográfica

EAS Publications Series, Volume 48, 2011, pp.13-18

Fecha de publicación:
7
2011
Número de autores
14
Número de autores del IAC
0
Número de citas
1
Número de citas referidas
1
Descripción
The NIR Ca II triplet has proven to be an important tool for quantitative spectroscopy. Here we present results of synthetic spectral analysis for the Ca II triplet for low-metallicity red giant stars, combined with observational data. Our results start to deviate strongly from the widely-used and linear empirical calibrations below [Fe/H] = -2. We provide a new calibration for Ca II triplet studies which is valid down until [Fe/H] = -4 and apply this new calibration to current data sets. We suggest that the classical dwarf galaxies are not so devoid of extremely low-metallicity stars as was previously thought and discuss preliminary results and possibilities for follow-up observations of these extremely low-metallicity candidates.