text: 388,69,1073063838814154753,321794593,José G. Fernández-Trincado,"Check out our new APOGEE paper published today on ArXiv: ""APOGEE [C/N] Abundances Across the Galaxy ...""<LINK> -- Great Sten! ""However, there have been discoveries of chemically anomalous N-enhanced field stars in the APOGEE data (see, e.g., Fernández-Trincado et al. 2016, 2017; Schiavon et al. 2017), which might show up in our sample as low-[C/N] stars... ""These stars are few in number (11 found in the disk), and generally exhibit [Fe/H] &lt; −0.5, so their contribution to the gradient and migration analysis is likely insignificant.""",https://arxiv.org/abs/1812.05092,"We present [C/N]-[Fe/H] abundance trends from the SDSS-IV Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey, Data Release 14 (DR14), for red giant branch stars across the Milky Way Galaxy (MW, 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 anti-correlation between age and metallicity, which is predicted by simple chemical evolution models, is not present at any Galactic zone. Stars far from the plane ($|$Z$|$ $>$ 1 kpc) exhibit a radial gradient in [C/N] ($\sim$ $-$0.04 dex/kpc). The [C/N] dispersion increases toward the plane ($\sigma_{[C/N]}$ = 0.13 at $|$Z$|$ $>$ 1 kpc to $\sigma_{[C/N]}$ = 0.18 dex at $|$Z$|$ $<$ 0.5 kpc). We measure a disk metallicity gradient for the youngest stars (age $<$ 2.5 Gyr) of $-$0.060 dex/kpc from 6 kpc to 12 kpc, which is in agreement with the gradient found using young CoRoGEE stars by Anders et al. Older stars exhibit a flatter gradient ($-$0.016 dex/kpc), 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]. ","APOGEE [C/N] Abundances Across the Galaxy: Migration and Infall from Red