Resolved near-infrared spectroscopy of the mysterious pre-main-sequence binary system T Tauri S.
DUCHENE G., GHEZ A.M. and McCABE C.
Abstract (from CDS):
We obtained new near-infrared images of the prototypical pre-main-sequence triple system T Tau, as well as the first resolved medium-resolution spectra of the close pair T Tau S. At the time of our observations, the tight binary had a 13 AU projected separation and showed significant motion since its discovery 3 yr before. The orbit cannot be strongly constrained yet, but the observed motion of T Tau Sb with respect to T Tau Sa suggests that the system is at least as massive as T Tau N itself. This may indicate that T Tau N is not the most massive star in the system. The spectrum of T Tau Sa, which is totally featureless except for a strong Brγ emission line, identifies this component with the ``infrared companion'', whose exact nature remains obscure but may be the consequence of its being the most massive component of the system. Contrasting sharply with T Tau Sa, the spectrum of T Tau Sb shows numerous photospheric features consistent with an early-M spectral type. The presence of a strong Brγ emission line and of a significant veiling continuum classifies this object as a deeply embedded T Tauri star. From these observations, we conclude that both components of T Tau S are embedded in their own dense circumstellar cocoons of material, which are probably fed by a much more extended structure.
Stars: Binaries: Close - Stars: Circumstellar Matter - Stars: Individual: Constellation Name: T Tauri S - Stars: Pre-Main-Sequence