Bibcode
Mathieu, R. D.; Martin, E. L.; Magazzu, A.
Referencia bibliográfica
American Astronomical Society, 188th AAS Meeting, #60.05; Bulletin of the American Astronomical Society, Vol. 28, p.920
Fecha de publicación:
9
1996
Número de citas
25
Número de citas referidas
20
Descripción
We have monitored spectroscopically the classical T Tauri star UZ Tau
East. Most observations were obtained with the Intermediate Dispersion
Spectrograph at the Isaac Newton Telescope in La Palma Observatory.
Several additional spectra were obtained with other telescopes at La
Palma, ESO and Lick observatories. Radial velocities were measured via
cross correlation with UZ Tau West. In total we have so far 18 radial
velocity measurements spanning 2627 days (Nov 1988 -- March 1996). The
radial-velocity data are well fit (sigma =2.3 km s(-1) ) with a
single-line orbit solution having a period of 19.1 days, an eccentricity
e=0.28, and a K of 17 km s(-1) . The projected primary semi-major axis
is a sini = 0.03 AU. The orbit parameters are not yet definitive because
the phase sampling is not thorough. After GW Ori and DQ Tau, UZ Tau E is
the third classical T Tauri spectroscopic binary for which an orbit has
been derived. A massive (0.06 Msun) circumbinary disk has
been resolved at millimeter wavelengths (Jensen et al. 1996, ApJ, in
press). Interestingly, UZ Tau E has a power-law infrared spectral energy
distribution with no evident dip suggesting an inner region cleared by
the binary. In addition, UZ Tau E is spectroscopically active with both
veiling and emission lines, indicative of active accretion at a stellar
surface despite the close companion. With this discovery UZ Tau becomes
a quadruple system, as UZ Tau West is a speckle binary with a projected
separation of 50 AU.