NOAO >   Observing Info >   Approved Programs >   2015A-0063

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Program Information for 2015A-0063


PI: Thomas Lebzelter, Universitat Wien (University of Vienna), thomas.lebzelter@univie.ac.at
Address: Department of Astrophysics, Tuerkenschanzstrasse 17, Vienna A1180 Austria

CoI: Kenneth H Hinkle, NOAO
CoI: Walter Nowotny, Universitat Wien (University of Vienna)
CoI: Peter Wood, Australian National U.
CoI: Oscar Straniero, INAF

Title: Dredge-up and the Period-Luminosity-Mass-Abundance relation of AGB stars

Abstract: Asymptotic Giant Branch (AGB) stars play a key role in the cosmic matter cycle. However, among other issues a proper understanding of the mixing processes, responsible for bringing material to the surface and into the mass loss zone, remains a major challenge. Among the important observational tools to study mixing in these stars are the isotopic ratios of C and O. Recent measurements obtained at KPNO by the proposers suggest a link between the variability periods of AGB stars and their $^{12}$C/$^{13}$C ratios. For variables with periods between 60 and 300 days, likely first overtone pulsators, there is a splitting into stars with no indications for mixing and stars with $^{12}$C/$^{13}$C increasing with periods. We argue that this is the result of mass differences among AGB stars with the same luminosity and pulsation period. With this proposal we will study this relation with the goal of defining a Period-Luminosity-Mass-Abundance relation for AGB variables in the solar neighborhood and a better understanding of the mixing efficiency.

Program Type: Standard/Galactic

Scheduled Nights:
Run 1 (2015A):  KP-4m/PHNX -- 2.5n on May 26 - May 28 2015


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NOAO >   Observing Info >   Approved Programs >   2015A-0063

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