NOAO >   Observing Info >   Approved Programs >   2012B-0512

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Proposal Information for 2012B-0512


PI: Isaac Shivvers, UC Berkeley, ishivvers@berkeley.edu
Address: Astronomy Department, D-301 Hearst Field Annex, Berkeley, California 94720-3411, USA

CoI: Joshua Bloom, UC Berkeley

Title: Observationally Constraining the Effects of Orbital Circularization for Stars in Binary Orbits

Abstract: Empirical determinations of the mass-radius-luminosity relations for main-sequence stars have, in general, used binary systems with circular orbits. However, binaries are expected to form with a wide range of primordial eccentricities and evolve towards circularity through tidal interactions. Such an evolutionary process may affect the interrelationships between mass, radius, and luminosity through tidal heating and inflation or other mechanisms. These effects may conspire to make binary systems in circularized orbits a biased source of information about single stars. The historical use of circularized binaries is due to observational restrictions, not choice. We therefore propose to obtain spectra and photometry of 9 bright and highly eccentric detached binaries as part of a program to obtain the absolute parameters of stars that have largely not undergone the processes that drive circularization. These specific targets were chosen as a pilot set to yield errors of ~ 1-2% in calculated parameters, similar to those of the best characterizations of binary systems in the literature. Using these we will directly examine the dependence of the mass, radius, and luminosity interrelationships upon circularization.


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