* Astronomy

Title: Detached Red Giant Eclipsing Binary Twins: Rosetta Stones to the Galactic Bulge
Authors: David M. Nataf, Andrew Gould, Marc H. Pinsonneault

We identify 34 highly-probable detached, red giant eclipsing binary pairs among 315 candidates in Devor's catalogue of ~10,000 OGLE-II eclipsing binaries. We estimate that there should be at least 200 such systems in OGLE-III. We show that spectroscopic measurements of the metallicities and radial-velocity-derived masses of these systems would independently constrain both the age-metallicity and helium-metallicity relations of the Galactic Bulge, potentially breaking the age-helium degeneracy that currently limits our ability to characterise the Bulge stellar population. Mass and metallicity measurements alone would be sufficient to immediately validate or falsify recent claims about the age and helium abundance of the Bulge. A spectroscopic survey of these systems would constrain models of Milky Way assembly, as well as provide significant auxiliary science on research questions such as mass loss on the red giant branch. We discuss the theoretical uncertainties in stellar evolution models that would need to be accounted for to maximise the scientific yield.

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