Image of Alice in Wonderland at the Mad Hatter's tea party You are cordially invited to afternoon tea and biscuits wine and chocolate

Astronomy Tea Talks at Caltech

Mondays, Hameetman auditorium (Cahill)
Tea:  4.00pm
Talk: 4.15pm

Organized by:

2011 - 2012 season:
26 September 2011 David Nataf (The Ohio State University)

'Probing the Age and Helium Enrichment of the Galactic Bulge with the Red Giant Branch Bump'

I discuss ongoing measurements of the red giant branch bump in globular clusters and the Galactic bulge, as well as comparisons with models, and how these measurements can be combined to yield a unique probe of the age-metallicity-helium relationship in the bulge. Using the OGLE-III bulge photometric survey, we find that the bulge RGBB may indicate a much higher level of helum enrichment than that observed in globular clusters, closer to Y~0.31 than Y~0.27 for stars at solar metallicity. In addition, I discuss how the Bump parameters are distinct toward double-clump sightlines, implying the presence of a helium gradient corresponding to the metallicity gradient.
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Image of the Mad Hatter from Alice in Wonderland
Last modified on 22nd Sep 2011 by Marco Viero.  

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