NOAO >   Observing Info >   Approved Programs >   2016A-0255

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Program Information for 2016A-0255


PI: Elliott Horch, SCSU, horche2@southernct.edu
Address: Department of Physics, 501 STREET, NEW HAVEN, CT 06515 USA

CoI: William van Altena, Yale U.
CoI: Pierre Demarque, Yale U.

Title: Towards a True Population II Mass-Luminosity Relation

Abstract: This proposal seeks time to obtain DSSI speckle observations of sixteen southern binary systems that will immediately impact the current understanding of the role of metallicity on the mass-luminosity relation. Twelve of the targets are already known to be spectroscopic binaries, and the remaining four have been resolved recently by speckle observations at very small separation at the SOAR telescope. A Gemini observation is now needed to "anchor" the calculation of a high-precision visual orbit as well as to give better-determined individual magnitudes and colors. These systems all have Hipparcos distances and most have mass fractions, so individual masses will immediately follow in most cases. With the full data set, it will not only be possible to make a major contribution to the main-sequence mass-luminosity relation for metal-poor stars, but also to conduct sensitive tests of the details of metal-poor stellar evolution models. For the lowest metallicity members in the sample, component colors and magnitudes would yield new points on the empirical Population II main sequence, which is important for the calibration of ages and distances to globular clusters and therefore our understanding of early Galaxy evolution.

Program Type: Standard/Galactic

Scheduled Nights:
Run 1 (2016A):  GEM-S-SVC/DSSI -- 5.3hrs band 1 (GS-2016A-Q-26)


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



NOAO >   Observing Info >   Approved Programs >   2016A-0255

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