AAS 204th Meeting, June 2004
Session 21 Moon, Mercury, Vesta and Late Stellar Evolutio
Oral, Monday, May 31, 2004, 10:00-11:30am, 610/612

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[21.07] Testing the Waters for GAIA's Galactic Structure Mission: Binary Stars as Probes of GAIA's Expected Performance

E.F. Milone (RAO, U. of Calgary, Canada), U. Munari (Oss. Astronomico di Padova; CISAS, Asiago, Italy), P.M. Marrese (Oss. Astronomico di Padova, Asiago and Dipt. Astronomia, U. di Padova, Italy), T. Zwitter (University of Ljubljana, Slovenia), J. Kallrath (BASF-AG, Ludwigshafen, Germany; Dept. of Astronomy, University of Florida), M.D. Williams (RAO, U. of Calgary, Canada)

ESA's cornerstone GAIA space mission, to be launched possibly at the end of the decade, is designed to explore the structure of the galaxy (with substantial capability even beyond the Milky Way), by encompassing micro-arc-sec astrometry, multi-passband photometry, and radial velocity-quality spectroscopy capability.

In a series of papers, we, with other colleagues, have analysed 12 eclipsing eclipsing binaries of all types to test GAIA's capability to yield sufficiently precise and accurate data to improve the cache of fundamental parameters for EB and SB2 systems with adequately sampled light and RV curves. To do this we have used Hipparcos and Tycho photometry and RVs obtained with Asiago's 1.8-m telescope and echelle spectrograph, sampling the same Ca triplet spectral region at similar spectral resolution to that selected for GAIA. Because the Hipparcos and Tycho data have less precision than that expected from GAIA, results are conservative. The systems studied were: V505 Per, V570 Per, OO Peg (Paper 1); V781 Tau, UV Leo, GK Dra (2); UW LMI, V432 Aur, and CN Lyn (3); SV Cam, BS Dra, and HP Dra (4). Two more papers in the series, and detailed follow-up studies, now completed for two of the systems, are planned .

The analyses have been carried out with our modified versions of the Wilson-Devinney program. We achieved precision as good as 0.5% in semi-major axis, 2.4% in radius, 1.8% in mass, 1.1% in mass ratio, 0.4% in systemic velocity, and 0.6 deg in inclination; in addition, uncertainties of less than 2% were achievable in the temperatures. The results bear out expectations of GAIA, which may provide more than an order of magnitude increase in the numbers of stars for which fundamental parameters can be determined to the 1% level.

This work was supported in part by the Osservatorio Astronomico di Padova; the Italian Space Agency, and ASI grants to CISAS and to UM; Slovenian Ministries of Education and of Research and Technology grants to TZ, and NSERC of Canada grants to EFM.

The author(s) of this abstract have provided an email address for comments about the abstract: milone@ucalgary.ca

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