N2H+Observations of Molecular Cloud Cores in Taurus

N2H+ observations of molecular cloud cores in Taurus with the Nobeyama 45 mradio telescope are reported. We compare ``cores with young stars'' with``cores without young stars''. The differences in core radius, linewidth, andcore mass are small. Linewidth is dominated by thermal motions in both cases.N2H+ maps show that the intensity distribution does not differ much betweencores without stars and those with stars. This is in contrast to the resultpreviously obtained in H13CO+ toward Taurus molecular cloud cores. Largerdegree of depletion of H13CO+ in starless cores will be one possibleexplanation for this difference. We studied the physical state of molecularcloud cores in terms of ``critical pressure'' for the surface (external)pressure. There is no systematic difference between starless cores and coreswith stars in this analysis. Both are not far from the critical state forpressure equilibrium. We suggest that molecular cloud cores in which thermalsupport is dominated evolve toward star formation by keeping close to thecritical state. This result is in contrast with that obtained in theintermediate-mass star forming region OMC-2/3, where molecular cloud coresevolve by decreasing the critical pressure appreciably. We investigate theradial distribution of the integrated intensity. Cores with stars are found tohave shallow (-1.8 to -1.6) power-law density profiles.Comment: 19 pages, 5 figure