NOAO >   Observing Info >   Approved Programs >   2011B-0424

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Proposal Information for 2011B-0424


PI: Maria Morales-Calderon, Caltech, mariamc@ipac.caltech.edu
Address: IPAC, 1200 E California Blvd, Pasadena, CA 91125, USA

CoI: John Stauffer, IPAC/Caltech
CoI: Keivan Stassun, Vanderbilt University
CoI: David James, NOAO
CoI: Steve Margheim, Gemini Observatory

Title: Confirmation and Characterization of Four New Low-Mass Pre-Main-Sequence Eclipsing Binaries in Orion

Abstract: Studies of eclipsing binary (EB) stars are key to accurate, empirical measurements of the masses, radii, and temperatures of stars, which are necessary for understanding stellar evolution and for deriving well-calibrated theoretical models. However, only seven pre-main- sequence (PMS) EBs with masses below 1.5 M_\odot have so far been published. We have discovered five new PMS EBs in Orion. Once fully characterized, these new systems will include the highest-mass PMS EB yet discovered in the Orion Nebula Cluster (ONC) and the lowest-mass PMS EB yet discovered anywhere. These new EBs were discovered as part of the YSOVAR project, which includes long-term photometric monitoring observations in the optical and near-infrared from ground-based telescopes, and in the mid-infrared from Spitzer. Thus we have excellent multi-wavelength light curves in hand for all of these EBs ready for detailed modeling and analysis. Here we propose to obtain multi-epoch spectroscopy from which we will measure the radial-velocity orbits of the EBs, which together with our light curves will permit the determination of accurate stellar masses, radii, temperatures, gravities, and luminosities for these very young, low-mass EBs. These EBs will substantially increase the number of benchmarks PMS stars over a large range of masses. The faintest system in our sample promises to be the lowest mass PMS EB known to date, and will double the number of brown-dwarf EBs known, providing a critically needed benchmark for theoretical stellar evolution models in the sub-stellar domain.


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



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