TY - JOUR
T1 - APOGEE [C/N] Abundances across the galaxy
T2 - Migration and infall from red giant ages
AU - Hasselquist, Sten
AU - Holtzman, Jon A.
AU - Shetrone, Matthew
AU - Tayar, Jamie
AU - Weinberg, David H.
AU - Feuillet, Diane
AU - Cunha, Katia
AU - Pinsonneault, Marc H.
AU - Johnson, Jennifer A.
AU - Bird, Jonathan
AU - Beers, Timothy C.
AU - Schiavon, Ricardo
AU - Minchev, Ivan
AU - Fernández-Trincado, J. G.
AU - Garciá-Hernández, D. A.
AU - Nitschelm, Christian
AU - Zamora, Olga
N1 - Funding Information:
D.A.G.H. and O.Z. acknowledge support provided by the Spanish Ministry of Economy and Competitiveness (MINECO) under grant AYA-2017-88254-P. T.C.B. acknowledges partial support for this work from grant PHY 14-30152, Physics Frontier Center/JINA Center for the Evolution of the Elements (JINA-CEE), awarded by the US National Science Foundation. The authors thank Ohio Stateʼs Center for Cosmology and AstroParticle Physics for hosting an APOGEE workshop where substantial progress was made on this project.
Funding Information:
Funding for the Sloan Digital Sky Survey IV has been provided by the Alfred P. Sloan Foundation, the U.S. Department of Energy Office of Science, and the Participating Institutions.
Publisher Copyright:
© 2019 The American Astronomical Society. All rights reserved.
PY - 2019/2/1
Y1 - 2019/2/1
N2 - We present [C/N]-[Fe/H] abundance trends from the SDSS-IV Apache Point Observatory Galactic Evolution Experiment survey, Data Release 14 (DR14), for red giant branch stars across the Milky Way (3 kpc < R < 15 kpc). The carbon-to-nitrogen ratio (often expressed as [C/N]) can indicate the mass of a red giant star, from which an age can be inferred. Using masses and ages derived by Martig et al., we demonstrate that we are able to interpret the DR14 [C/N]-[Fe/H] abundance distributions as trends in age-[Fe/H] space. Our results show that an anticorrelation between age and metallicity, which is predicted by simple chemical evolution models, is not present at any Galactic zone. Stars far from the plane ( kpc) exhibit a radial gradient in [C/N] (∼-0.04 dex kpc -1 ). The [C/N] dispersion increases toward the plane (σ [C/N] = 0.13 at kpc to σ [C/N] = 0.18 dex at |Z| < 0.5 kpc). We measure a disk metallicity gradient for the youngest stars (age < 2.5 Gyr) of-0.060 dex kpc -1 from 6 to 12 kpc, which is in agreement with the gradient found using young CoRoGEE stars by Anders et al. Older stars exhibit a flatter gradient (-0.016 dex kpc -1 ), which is predicted by simulations in which stars migrate from their birth radii. We also find that radial migration is a plausible explanation for the observed upturn of the [C/N]-[Fe/H] abundance trends in the outer Galaxy, where the metal-rich stars are relatively enhanced in [C/N].
AB - We present [C/N]-[Fe/H] abundance trends from the SDSS-IV Apache Point Observatory Galactic Evolution Experiment survey, Data Release 14 (DR14), for red giant branch stars across the Milky Way (3 kpc < R < 15 kpc). The carbon-to-nitrogen ratio (often expressed as [C/N]) can indicate the mass of a red giant star, from which an age can be inferred. Using masses and ages derived by Martig et al., we demonstrate that we are able to interpret the DR14 [C/N]-[Fe/H] abundance distributions as trends in age-[Fe/H] space. Our results show that an anticorrelation between age and metallicity, which is predicted by simple chemical evolution models, is not present at any Galactic zone. Stars far from the plane ( kpc) exhibit a radial gradient in [C/N] (∼-0.04 dex kpc -1 ). The [C/N] dispersion increases toward the plane (σ [C/N] = 0.13 at kpc to σ [C/N] = 0.18 dex at |Z| < 0.5 kpc). We measure a disk metallicity gradient for the youngest stars (age < 2.5 Gyr) of-0.060 dex kpc -1 from 6 to 12 kpc, which is in agreement with the gradient found using young CoRoGEE stars by Anders et al. Older stars exhibit a flatter gradient (-0.016 dex kpc -1 ), which is predicted by simulations in which stars migrate from their birth radii. We also find that radial migration is a plausible explanation for the observed upturn of the [C/N]-[Fe/H] abundance trends in the outer Galaxy, where the metal-rich stars are relatively enhanced in [C/N].
KW - Galaxy: Abundances
KW - Galaxy: Disk
KW - Galaxy: Evolution
UR - http://www.scopus.com/inward/record.url?scp=85062022689&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85062022689&partnerID=8YFLogxK
U2 - 10.3847/1538-4357/aaf859
DO - 10.3847/1538-4357/aaf859
M3 - Article
AN - SCOPUS:85062022689
VL - 871
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 2
M1 - 181
ER -