Lifting the Veil on Ultra Metal-Poor Stars in the Milky Way

Data: 
13/09/2017 - 14:00 - 15:00
Local: 
IAG - Aud. Principal, Bloco G

Lifting the Veil on Ultra Metal-Poor Stars in the Milky Way

 

Timothy C. Beers

University of Notre Dame

 

There are only some two dozen stars known with [Fe/H] < -4.0, the so-called Ultra Metal-Poor (UMP) stars, despite searching for them by numerous researchers over the past few decades.  Yet these stars hold the key to understanding the nucleosynthesis processes assocated with the very first (presumably massive) stars in the Universe.  Recent numerical simulations of the assembly of the Milky Way now make it clear why UMP stars have proven so difficult to find in the relatively nearby search volume that has been surveyed to date.  They live, primarily, in the outskirts of the Galaxy, the outermost halo, with apparent magnitudes as faint as g ~ 20.  We have already begun a survey to identify these stars, using the Large Binocular Telescope and Gemini-S.   In this talk I present evidence for their existence, highlight examples of such stars that have already been found, and describe our plans to dramatically increase the numbers of UMP stars known in the near future.