, S.Guilloteau 
, G.Duvert 
,
L.Prato 
, M.Simon 
, K.Schuster 
, F.Ménard 
Institut de Radio Astronomie Millimétrique,
300 Rue de la Piscine, F-38406 Saint Martin d'Hères, France
Laboratoire d'Astrophysique de Grenoble, B.P. 53, F-38041 Grenoble
Cedex 9, France
Astronomy Program, State Univ. of New York, Stony Brook, NY 11794-2100, U.S.A. 
and 2.7 mm 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.
Figure 7: Continuum images of the observed stars. Contour steps are
-4, -2, 2, 4, 6, 8 and then 10 to 50 by 5 mJy/beam. The name of
the source is indicated in upper left corner, and the beam size
in lower left. The crosses indicate the nominal position of the stars
from HBC. Coordinates are in the J2000 system.
Positions have been
corrected for proper motions according to measurements by Jones and Herbig
(1979) and Hartmann et al. (1991).
Figure 8: Continuum images of the observed stars (cont.).
The upper limits for IW Tau, IS Tau, GH Tau, GK Tau and LkCa 3
(not shown here) were obtained with a beam similar to that of DM Tau.
For UY Aur, we show two maps, one obtained at full resolution (left), the
other (right) done with a 150-m taper. Since Haro 6-5b is displaced
from the pointing center FS Tau, the map has
been corrected from the primary beam attenuation. The S/N in this map
decreases towards the north-west of the map, and contours to the north
and north-west of Haro 6-5b are noise peaks.
Note that GM Aur position has not been corrected for proper motion.
We detected 2.7 mm continuum emission in 12
systems at S/N >5 and have probable detections for another 5. V 773 Tau, a weak emission line binary system, is remarkable in that its 2.7 mm
continuum decreased from 
mJy to 
mJy 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 1.3 mm. Significant estimates of the
sizes have been obtained for 8 singles. They imply large (R > 150 AU)
disks, with relatively flat density distribution (emissivity
flatter than 
). The spectral
energy distributions in the millimeter range can be fitted
using a dust emissivity law 
with
value of 
in the range 0.5 to 1.
Only DG Tau, Haro 6-5b and UY Aur have detectable 
emission.
emission, but no 2.7 mm continuum, is also found in the
LkH
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 2.7 mm are more than a factor of
about 20 larger than the masses derived from the 
upper limit.
To appear in A&A main journal.
The
full preprint
is available as a postscript file.