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We present interferometric observations with resolution of ~3 arcsecs of theisolated, low-mass protostellar double cores CG30 and BHR71 in the N2$H+(1-0)line and at 3mm dust continuum, using the Australian Telescope Compact Array(ATCA). The results are complemented by infrared data from the Spitzer SpaceTelescope. In CG30, the 3mm dust continuum images resolve two compact sourceswith a separation of ~21.7 arcsecs (~8700 AU). In BHR71, strong dust continuumemission is detected at the position of the mid-infrared source IRS1, whileonly weak emission is detected from the secondary mid-infrared source IRS2.Assuming optically thin 3mm dust continuum emission, we derive hydrogen gasmasses of 0.05--2.1 $M_\odot$ for the four sub-cores. N2H+(1-0) line emissionis detected in both CG30 and BHR71, and is spatially associated with thethermal dust continuum emission. We derive the velocity fields and findsymmetric velocity gradients in both sources. Assuming that these gradients aredue to core rotation, we estimate the specific angular momenta and ratios ofrotational energy to gravitational energy for all cores. We also find that theN2H+ emission is strongly affected by the outflows, both in terms ofentrainment and molecule destruction. $Spitzer$ images show the mid-infraredemission from all four sub-cores. All four sources appear to drive their ownoutflows. Based on the ATCA and $Spitzer$ observations, we construct spectralenergy distributions (SEDs) and derive temperatures and luminosities for allcores. Based on the morphology and velocity structure, we suggest that thesub-cores in CG30 were formed by initial fragmentation of a filamentaryprestellar core, while those in BHR71 could originate from rotationalfragmentation of a single collapsing protostellar core.

ATCA and Spitzer Observations of the Binary Protostellar Systems CG30 and BHR71