The Pristine Survey -- VI. The first three years of medium-resolution follow-up spectroscopy of Pristine EMP star candidates
astro-ph.GA
/ Authors
David S. Aguado, Kris Youakim, Jonay I. González Hernández, Carlos Allende Prieto, Else Starkenburg, Nicolas Martin, Piercarlo Bonifacio, Anke Arentsen, Elisabetta Caffau, Luis Peralta de Arriba
and 20 more authors
Federico Sestito, Rafael Garcia-Diaz, Nicholas Fantin, Vanessa Hill, Pascale Jablonca, Farbod Jahandar, Collin Kielty, Nicolas Longeard, Romain Lucchesi, Rubén Sánchez-Janssen, Yeisson Osorio, Pedro A. Palicio, Eline Tolstoy, Thomas G. Wilson, Patrick Côté, Georges Kordopatis, Carmela Lardo, Julio F. Navarro, Guillaume F. Thomas, Kim Venn
/ Abstract
We present the results of a 3-year long, medium-resolution spectroscopic campaign aimed at identifying very metal-poor stars from candidates selected with the CaHK, metallicity-sensitive Pristine survey. The catalogue consists of a total of 1007 stars, and includes 146 rediscoveries of metal-poor stars already presented in previous surveys, 707 new very metal-poor stars with [Fe/H] < -2.0, and 95 new extremely metal-poor stars with [Fe/H] < -3.0. We provide a spectroscopic [Fe/H] for every star in the catalogue, and [C/Fe] measurements for a subset of the stars (10% with [Fe/H] < -3 and 24% with -3 < [Fe/H] < -2) for which a carbon determination is possible, contingent mainly on the carbon abundance, effective temperature and S/N of the stellar spectra. We find an average carbon enhancement fraction ([C/Fe] >= +0.7) of 41 +- 4% for stars with -3 < [Fe/H] < -2 and 58 +- 14% for stars with [Fe/H] < -3, and report updated success rates for the Pristine survey of 56 % and 23 % to recover stars with [Fe/H] < -2.5 and [Fe/H] < -3, respectively. Finally, we discuss the current status of the survey and its preparation for providing targets to upcoming multi-object spectroscopic surveys such as WEAVE.