An observational study of the evolution of low mass protostars in interstellar molecular clouds

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We have built the new 4m mm-wave telescope, and improved the sensitivity of the supercoducting receiver. The telescope shows a remarkably high capability in observing mm-wave radiation. The best receiver temperature achieved is as low as 20K in DSB,the best value reported so far in the literature. The main results from the research are as follows ;1.Discovery of 62 molecular outflows. This number corresponds to one third of the total discovered so far.2.Complete observations of the 13CO emission in the Orion A region, Taurus and Ophiuchus (150,000 spectra).3.Complete survey for dense cores in the above three regions in the C18O emission (15,000 spectra).4.CS survey for Orion and Ophiuchus (4,000 spectra).5.Detection of the gas disk in GG Tau, a young T Tauri.By analysing these data sets, we have obtained the basic properties of dense cores and their time scales, and also have located the molecular outflow as the main accretion phase in the protostellar evolution. These outcomes provide valuable observational constraints on star formation.