1996A&A...309..493D

We present new ¹³CO J=1->0 and 2.7mm continuum interferometric observations of 33 young star systems located in Taurus-Auriga. Our goal was to compare the distribution, and hence the evolution, of the circumstellar material around young star singles and binaries. The sample included 2 triples, 16 binaries, 14 singles, and one object of unknown multiplicity. We detected 2.7mm continuum emission in 12 systems at S/N>5 and have probable detections for another 5. V773 Tau, a weak emission line binary system, is remarkable in that its 2.7mm continuum decreased from ∼30mJy to ∼0mJy in less than six months. We find that the singles are, on average, stronger 2.7 continuum sources than the multiples, consistent with Osterloh & Beckwith's (1995) finding at 1.3mm. Significant estimates of the sizes have been obtained for 8 singles. They imply large (R>150AU) disks, with relatively flat density distribution (emissivity flatter than r^–1.5). The spectral energy distributions in the millimeter range can be fitted using a dust emissivity law K_ν∝ν^β with value of β in the range 0.5 to 1. Only DG Tau, Haro 6-5b and UY Aur have detectable ¹³CO J=1->0 emission. ¹³CO emission, but no 2.7mm continuum, is also found in the LkHα 332 region and near FS Tau; however, it does not appear to be associated with the known stars. Interpreting the observational results in terms of the circumstellar disk scenario, we find that, in all cases, disk masses derived from the dust emission at 2.7mm are more than a factor of about 20 larger than the masses derived from the ¹³CO J=1->0 upper limit.