NOAO >   Observing Info >   Approved Programs >   2003B-0199

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Proposal Information for 2003B-0199


PI: Keivan G. Stassun, University of Wisconsin - Madison, keivan@astro.wisc.edu
Address: Astronomy Department, 475 North Charter Street, Madison, WI 53706, USA

CoI: Robert Mathieu, University of Wisconsin - Madison
CoI: Luiz Paulo Vaz, Instituto Federal de Minas Gerais, Brazil

Title: A Spectroscopic and Photometric Study of Newly Discovered Pre-Main- Sequence Eclipsing Binaries in Orion

Abstract: The discovery and analysis of pre-main-sequence (PMS) eclipsing binary star systems is of critical importance to the study of star formation and young stellar populations. With only four PMS eclipsing binary systems presently known, the evolutionary tracks which are used to infer fundamental stellar properties such as masses and ages-and from which stellar initial mass functions are constructed-remain largely uncalibrated by empirical mass determinations, particularly in the sub-solar-mass regime. We have an intensive observing program underway to substantially increase the sample of low-mass PMS eclipsing binaries. In 2000B-2002A we completed our study of the first of these systems, SM790, which includes the lowest-mass (0.7 \rm M_\odot) PMS star yet discovered in an eclipsing binary. In 2002B we began a comprehensive spectroscopic and photometric study of two new eclipsing binaries in the Orion star-forming region. One of these, SM4147, is particularly interesting because its position in the color-magnitude diagram indicates its mass to be ~ 0.1 M_\odot, which would represent the first empirical mass determination for a PMS star at the stellar/sub-stellar boundary. We propose here to continue our study of these new PMS eclipsing binary systems. Specifically, we request (1) high-resolution spectra with \it Phoenix and HET/HRS providing precise double-lined orbits, and (2) photometric monitoring with the CTIO 0.9m and 1.3m to provide multi-band light curves for modeling and analysis.


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