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BEGIN:VEVENT
DTSTART;TZID=Atlantic/Canary:20190205T123000
DTEND;TZID=Atlantic/Canary:20190205T133000
UID:iactalks-1245
X-WR-CALNAME: IAC Talks: Open Astronomy Seminars
X-ORIGINAL-URL: /iactalks/Talks/view/1245
CREATED:2019-02-05T12:30:00+00:00
X-WR-CALDESC: IAC Talks upcomming talks
SUMMARY:[C/N] in red giants and across the Milky Way
DESCRIPTION:[C/N] in red giants and across the Milky Way\nDr. Matthew Shetr
 one\n\nDespite being some of the most abundant elements in the  Unive
 rse the determination and understanding of the chemical evolution  of
  C and N is still very uncertain.  One of the main limitations in und
 erstanding chemical evolution of C and N is the fact that C and N are alte
 red as during the first dredge-up on the red giant branch.   We 
 present old red giants at various metallicities and luminosities in a samp
 le that is more than 100 times larger than the seminal work of Gratton et 
 al. 2000. Using this we can see the impact of the first dredge-up as well 
 as the on set of "extra" mixing at the bump in the luminosity function for
  giants more metal-poor than [Fe/H] < -0.4. These observations can be u
 sed to constrain future models of mixing.    At a fixed met
 allicity younger stars have a stronger mixing response during dredge-up.&n
 bsp;  This fact allows up to infer ages from the first dredge-up [C/N
 ] ratio.   We demonstrate that we are able to interpret the DR14
  [C/N]-[Fe/H] abundance distributions as trends in age-[Fe/H] space. Our r
 esults show that an anti-correlation between age and metallicity, which is
  predicted by simple chemical evolution models, is not present at any Gala
 ctic zone. Stars far from the plane (|Z| > 1 kpc) exhibit a radial grad
 ient in [C/N]. The [C/N] dispersion increases toward the plane.  We m
 easure a disk metallicity gradient for the youngest stars from 6 kpc to 12
  kpc, which is in agreement with the gradient found from other surveys.&nb
 sp; Older stars exhibit a flatter gradient, which is predicted by simulati
 ons in which stars migrate from their birth radii. We also find that radia
 l 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].
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