TY - JOUR
T1 - The Pristine survey - IX. CFHT ESPaDOnS spectroscopic analysis of 115 bright metal-poor candidate stars
AU - Venn, Kim A.
AU - Kielty, Collin L.
AU - Sestito, Federico
AU - Starkenburg, Else
AU - Martin, Nicolas
AU - Aguado, David S.
AU - Arentsen, Anke
AU - Bonifacio, Piercarlo
AU - Caffau, Elisabetta
AU - Hill, Vanessa
AU - Jablonka, Pascale
AU - Lardo, Carmela
AU - Mashonkina, Lyudmilla
AU - Navarro, Julio F.
AU - Sneden, Chris
AU - Thomas, Guillaume
AU - Youakim, Kris
AU - González-Hernández, Jonay I.
AU - Sánchez Janssen, Rubén
AU - Carlberg, Ray
AU - Malhan, Khyati
PY - 2020/3
Y1 - 2020/3
N2 - A chemo-dynamical analysis of 115 metal-poor candidate stars selected from the narrow-band Pristine photometric survey is presented based onCFHT high-resolution ESPaDOnS spectroscopy. We have discovered 28 new bright (V < 15) stars with [Fe/H] < -2.5 and 5 with [Fe/H] <-3.0 for success rates of 40 (28/70) and 19 per cent (5/27),respectively. A detailed model atmosphere analysis is carried out for the 28 new metal-poor stars. Stellar parameters were determined fromSDSS photometric colours, Gaia DR2 parallaxes, MESA/MIST stellar isochrones, and the initial Pristine survey metallicities, following aBayesian inference method. Chemical abundances are determined for 10elements (Na, Mg, Ca, Sc, Ti, Cr, Fe, Ni, Y, and Ba). Most stars show chemical abundance patterns that are similar to the normal metal-poor stars in the Galactic halo; however, we also report the discoveries of anew r-process-rich star, a new CEMP-s candidate with [Y/Ba] > 0, and a metal-poor star with very low [Mg/Fe]. The kinematics and orbits for all of the highly probable metal-poor candidates are determined by combining our precision radial velocities with Gaia DR2 proper motions.Some stars show unusual kinematics for their chemistries, including planar orbits, unbound orbits, and highly elliptical orbits that plunge deeply into the Galactic bulge (Rperi < 0.5 kpc); also, eight stars have orbital energies and actions consistent with theGaia-Enceladus accretion event. This paper contributes to our
understanding of the complex chemo-dynamics of the metal-poor Galaxy, and increases the number of known bright metal-poor stars available for detailed nucleosynthetic studies.
AB - A chemo-dynamical analysis of 115 metal-poor candidate stars selected from the narrow-band Pristine photometric survey is presented based onCFHT high-resolution ESPaDOnS spectroscopy. We have discovered 28 new bright (V < 15) stars with [Fe/H] < -2.5 and 5 with [Fe/H] <-3.0 for success rates of 40 (28/70) and 19 per cent (5/27),respectively. A detailed model atmosphere analysis is carried out for the 28 new metal-poor stars. Stellar parameters were determined fromSDSS photometric colours, Gaia DR2 parallaxes, MESA/MIST stellar isochrones, and the initial Pristine survey metallicities, following aBayesian inference method. Chemical abundances are determined for 10elements (Na, Mg, Ca, Sc, Ti, Cr, Fe, Ni, Y, and Ba). Most stars show chemical abundance patterns that are similar to the normal metal-poor stars in the Galactic halo; however, we also report the discoveries of anew r-process-rich star, a new CEMP-s candidate with [Y/Ba] > 0, and a metal-poor star with very low [Mg/Fe]. The kinematics and orbits for all of the highly probable metal-poor candidates are determined by combining our precision radial velocities with Gaia DR2 proper motions.Some stars show unusual kinematics for their chemistries, including planar orbits, unbound orbits, and highly elliptical orbits that plunge deeply into the Galactic bulge (Rperi < 0.5 kpc); also, eight stars have orbital energies and actions consistent with theGaia-Enceladus accretion event. This paper contributes to our
understanding of the complex chemo-dynamics of the metal-poor Galaxy, and increases the number of known bright metal-poor stars available for detailed nucleosynthetic studies.
KW - Galaxy: stellar content
KW - Galaxy: kinematics and dynamics
KW - Galaxy: abundances
KW - stars: Population II
KW - stars: abundances
KW - stars: kinematics and dynamics
U2 - 10.1093/mnras/stz3546
DO - 10.1093/mnras/stz3546
M3 - Article
VL - 492
SP - 3241
EP - 3262
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 3
ER -