Mapping the Milky Way's assembly using stars as tools

Prof. Melissa Ness (Columbia University)
Tuesday, January 26, 2021 - 1:00pm

Galactic archaeology has entered a remarkable era, with Gaia and an ensemble of spectroscopic surveys providing chemical abundances and velocities for millions of stars. With the dramatic increase in data, there is an opportunity to understand its limitations: how can this data actually inform our Galactic history?  I will show some of the limitations (and opportunities) in using stellar spectra and derived chemical abundances for unraveling galactic history in the disk: 1 in 100 stars in high-resolution IR surveys of the disk are doppelgangers - identical but unrelated - impeding the prospect of chemical tagging with these data. Furthermore, many chemical abundances can be predicted to a precision of ~0.02 dex, given two measurements; [Fe/H] and age.  Such limitations frame how we can most effectively work with the data, to turn photons into a quantified description of Galactic history.

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