We have investigated the properties of the high-latitude cloud MBM 7 using the 3 mm transitions of CO, CS, HCN, HCO+,C3H2,N2H+, and SiO. The molecular component of MBM 7 shows a very clumpy structure with a size of ≤0.5 pc, elongated along the northwest-southeast direction, perpendicularly to an extended HI component, which could be resulted from shock formation. We have derived physical properties for two molecular cores in the central region. Their sizes are 0.1-0.3 pc and masses 1-2 M⊙ having an average volume density ~2×10 3 cm-3 at the peak of molecular emission. We have tested the stability of the cores using the full version of the virial theorem and found that the cores are stabilized with ambient medium, and they are expected not to be dissipated easily without external perturbations. Therefore MBM 7 does not seem to be a site for new star formation. The molecular abundances in the densest core appear to be much less (by about one order of magnitude) than the 'general' dark cloud values. If the depletions of heavy elements are not significant in the HLCs compared with those in typical dark clouds, our results may suggest different chemical evolutionary stages or different chemical environments of the HLCs compared with dense dark clouds in the Galactic plane.

An outline is given of our development of mosaic CCD cameras. Hardware and data reduction software of two operational cameras are described. Scientific objectives of wide-field imaging with the cameras are briefly described.

With the 14 m radio telescope at DRAO and the 4 m at Nagoya University, we have made detailed maps of 12 C O and 13 C O emissions from two Barnard objects B133 and B134 in the J = 1 → O rotational transition lines. Usual LTE analyses of the CO observations led us to determine the distribution of column densities over an entire area encompassing both globules. Total gas masses estimated from the column density map are 90 M ⊙ and 20 M ⊙ for B133 and B134, respectively. The radial velocity of B133 is red shifted with respect to B134 by 0.8 k m s − 1 , which is too lagre to bind the two clouds as a binary system. We have shown that the usual stability analysis based on the simplified version of virial theorem with the second time-derivative of the moment of inertia term ¨ I being ignored could mislead us in determining whether a given cloud eventually collapses or not. The lull version of the scalar virial theorem with the ¨ I term is shown to be useful in following up the time-dependent variations of the cloud size R and its streaming velocity ˙ R as functions of time. Results of our stability analysis suggest that B133 will eventually collapse in ( 2 ∼ 4 ) × 10 6 years.