THE STAR FORMATION NEWSLETTER An electronic publication dedicated to early stellar evolution and molecular clouds No. 131 — 8 September 2003 Editor: Bo Reipurth (
[email protected]) Abstracts of recently accepted papers The pre-main sequence spectroscopic binary AK Sco revisited S.H.P. Alencar1,2, C.H.F. Melo3, C.P. Dullemond4, J. Andersen5, C. Batalha6, L.P.R. Vaz1, and R.D. Mathieu7 1 Departamento de Fsica, ICEx-UFMG, CP. 702, Belo Horizonte - MG, 30123-970, Brazil 2 Departamento de Astronomia, IAG, USP, Rua do Mat˜ao,1226, S˜aoPaulo, 05508-900, Brazil 3 European Southern Observatory, Casilla 19001, Santiago 19, Chile 4 Max Planck Institut f¨urAstrophysik, Postfach 1317, D-85741 Garching, Germany 5 Niels Bohr Institute for Astronomy, Physics, and Geophysics, Astronomical Observatory, Juliane Maries Vej 30, 2100 Copenhagen, Denmark 6 Observat´orio Nacional, Departamento de Astrof´ısica, Rua General Jos´eCristino 77, S˜aoCrist´ov˜ao, Rio de Janeiro, 20921-400, Brazil 7 Department of Astronomy, University of Wisconsin-Madison, 475 North Charter Street, Madison, WI, 53706, USA E-mail contact: silvia@fisica.ufmg.br We present an analysis of 32 high-resolution echelle spectra of the pre-main sequence spectroscopic binary AK Sco obtained during 1998 and 2000, as well as a total of 72 photoelectric radial-velocity observations from the period 1986- 1994. These data allow considerable improvement of the period and other orbital parameters of AK Sco. Our analysis also includes eight series of photometric observations in the uvby and Geneva seven-color systems from 1987, 1989, 1990, 1992, 1994 and 1997.