Fernández-Trincado – The exotic chemical composition of giant stars discovered in the H-band of APOGEE


“The exotic chemical composition of giant stars discovered in the H-band of APOGEE”

J. G. Fernández-Trincado

Universidad de Concepcion

APOGEE contains more than hundred thousands new giant stars. This enabled us to collected an unprecedented and homogeneous sample of giant stars with light-element abundance variations similar to observed in “second-generation” globular cluster stars. If they are really former members of dissolved globular clusters, stars in these groups should show some of the basic SG-like chemical patterns known for stars currently belonging to the Milky Way globular clusters, such as depletion in C and O together with N and Al enrichment. Here, I will present the results of an updated census of SG-like stars from a near-infrared manual analysis using the Brussels Automatic Stellar Parameter (BACCHUS) code to provide the abundances of C, N, O, Mg, Si, Al, Fe, Ce and Nd for every line of possible cluster member stars, which they migrate to the disk, halo and bulge as unbound stars, and become part of the general stellar population of the Milky Way. By combining wide-field time-series photometry with APOGEE-2S spectroscopy data, we are in a good position to put the big picture together. The VVV survey have produced a large variability dataset towards the Milky Way bulge and disk, including data in the near-IR (J and Ks). These data will allow us to place constraints on the “polluters” that are responsible for the chemical peculiarities, with candidates including TP-AGB stars, binary mass transfer, accretion of material from the winds of AGB stars, etc. A cross match between VVV sources and APOGEE targets is ongoing.

Seminar room, Institute of Astronomy

Tuesday 14th August 2018