EDP Sciences
Free access
Volume 429, Number 3, January III 2005
Page(s) 939 - 943
Section Interstellar and circumstellar matter
DOI http://dx.doi.org/10.1051/0004-6361:20041724

A&A 429, 939-943 (2005)
DOI: 10.1051/0004-6361:20041724

The pre-main sequence spectroscopic binary UZ Tau East: Improved orbital parameters and accretion phase dependence

E. L. Martín1, 2, A. Magazzù3, X. Delfosse4 and R. D. Mathieu5

1  Instituto de Astrofísica de Canarias, 38200 La Laguna, Tenerife, Spain
    e-mail: ege@iac.es
2  University of Central Florida, Department of Physics, PO Box 162385, Orlando, FL 32816-2385, USA
    e-mail: ege@physics.ucf.edu
3  INAF - Telescopio Nazionale Galileo, Apartado 565, 38700, Santa Cruz de La Palma, Spain
    e-mail: magazzu@tng.iac.es
4  Laboratoire d'Astrophysique Observatoire de Grenoble, BP 53, 414 rue de la Piscine, 38041, Grenoble Cedex 9, France
    e-mail: delfosse@obs.ujf-grenoble.fr
5  Department of Astronomy, University of Wisconsin-Madison, 475 North Charter Street, Madison, WI 53706, USA
    e-mail: mathieu@astro.wisc.edu

(Received 23 July 2004 / Accepted 8 september 2004)

We present radial-velocity measurements obtained using high- and intermediate-resolution spectroscopic observations of the classical T Tauri star UZ Tau East from 1994 to 1996. We also provide measurements of H $\alpha$ equivalent widths and optical veiling. Combining our radial-velocity data with those recently reported by Prato et al. (2002), we improve the orbital elements for this spectroscopic binary. The orbital period is $18.979\pm0.007$ days and the eccentricity is e=0.14. We find variability in the H $_\alpha$ emission and veiling, signposts of accretion, but at periastron passage the accretion is not as clearly enhanced as in the case of the binary DQ Tau. The difference in the behaviour of these two binaries is consistent with the hydrodynamical models of accretion from circumbinary disks because UZ Tau East has lower eccentricity than DQ Tau. It seems that enhanced periastron accretion may occur only in systems with very high eccentricity ( e>0.5).

Key words: stars: binaries: spectroscopic -- stars: formation -- stars: late-type -- stars: pre-main sequence -- accretion, accretion disks -- stars: planetary systems: protoplanetary disks

SIMBAD Objects

© ESO 2005