Related papers: A fourth component in the young multiple system V …
We investigate the binary star T Tauri South, presenting the orbital parameters of the two components and their individual masses. We combined astrometric positions from the literature with previously unpublished VLT observations. Model…
We report spatially resolved spectroscopy of both components of the low-mass pre-main-sequence binary GV Tau. High resolution spectroscopy in the K- and L-bands is used to characterize the stellar properties of the binary and to explore the…
Context. This work is part of a long-term spectroscopic study of a sample of 30 multiple stars with early-type components. In this second paper we present the results of six multiple systems in which new stellar components have been…
The early-K star T Cha, a member of the relatively nearby (D ~ 100 pc) epsilon Cha Association, is a relatively "old" (age ~7 Myr) T Tauri star that is still sporadically accreting from an orbiting disk whose inner regions are evidently now…
Adaptive optics corrected images obtained with the CIAO instrument at the Subaru 8.2-meter telescope show the presence of two subarsecond companions to the nearby (d=19.3 pc) young star GJ 900, which was previously classified as a single…
We summarize here the observed properties of ``infrared companions'' to T Tauri stars and argue that their observational properties are identical to those of Class I sources. They may therefore be embedded protostars in a much earlier…
We report 3.6 cm continuum observations taken with the Very Large Array (VLA) of the young binary system UY Aur. The binary consists of a T Tauri star, UY Aur A, and a so-called ``infrared companion'' (IRC), UY Aur B, separated by 0.''89.…
We report spectroscopic observations of HD 27638B, the secondary in a visual binary in which the physically associated primary (separation approximately 19 arcsec) is a B9V star. The secondary shows strong Li 6708 absorption suggesting…
The optical star in the T Tauri triple system is the prototype of young sun-like stars in our galaxy. This complex and dynamic system has evidence for misaligned disks and outflows, and molecular material in a circumbinary ring that…
The young binary system T Tau was observed with the Owens Valley Millimeter Array at 267 GHz continuum and HCO+ J=3-2 emission at 0.8'' resolution, with the JCMT-CSO single-baseline interferometer in 357 GHz continuum, and with the W. M.…
We present new near-IR observations of 76 Class I/flat-spectrum objects in the nearby (d < 320 pc) Perseus, Taurus, Chamaeleon I and II, rho Ophiuchi, and Serpens dark clouds. These observations are part of a larger systematic infrared…
The stellar companion to the weak-line T Tauri star DI Tau A was first discovered by the lunar occultation technique in 1989 and was subsequently confirmed by a speckle imaging observation in 1991. It has not been detected since, despite…
We present the results of our monitoring study of the IR photometric and spectroscopic variability of the T Tau multiple system. We also present data on the apparent position of T Tau S with respect to T Tau N, and two new spatially…
We present results from a large, high-spatial-resolution near-infrared imaging search for stellar and sub-stellar companions in the Taurus-Auriga star-forming region. The sample covers 64 stars with masses between those of the most massive…
We present first results of a survey for companions among X-ray selected pre-main sequence stars, most of them being weak-line T Tauri stars (WTTS). These T Tauri stars have been identified in the course of optical follow-up observations of…
Preliminary results on the ongoing spectroscopic study of the six brightest Orion Trapezium stars is presented here. The main purpose of this work is to better understand the multiplicity and stability of each of these subsystems and the…
Young and close multiple systems are unique laboratories to probe the initial dynamical interactions between forming stellar systems and their dust and gas environment. Their study is a key building block to understanding the high frequency…
We present high-resolution imaging of the young binary T Tauri in 3 mm continuum emission. Compact dust emission with integrated flux density 50 +/- 6 mJy is resolved in an aperture synthesis map at 0.5" resolution and is centered at the…
$\xi$ Tau is one of the most compact multiple stellar systems, which is sufficiently close (67 pc) to be constrained by all kinds of observations. To better constrain its current configuration, we utilized new observational data: (i)…
We present spatially resolved near-infrared and mid-infrared (1-25 microns) imaging of the WL 20 triple system in the nearby (d=125 pc) rho Ophiuchi star-forming cloud core. We find WL 20 to be a new addition to the rare class of "infrared…