A Bubbling Nearby Molecular Cloud: Complete Shells in Perseus

We present a study of the shells (and bubbles) in the Perseus molecular cloud using the COMPLETE survey large-scale (CO)-C-12(1-0) and (CO)-C-13(1-0) maps. The 12 shells reported here are spread throughout most of the Perseus cloud and have circular or arc-like morphologies with a range in radius of about 0.1-3 pc. Most of them have not been detected before most likely because maps of the region lacked the coverage and resolution needed to distinguish them. The majority of the shells are coincident with infrared nebulosity of similar shape and have a candidate powering source near the center. We suggest that they are formed by the interaction of spherical or very wide angle winds powered by young stars inside or near the Perseus molecular cloud-a cloud that is commonly considered to be forming mostly low-mass stars. Two of the 12 shells are powered by high-mass stars close to the cloud, while the others appear to be powered by low-or intermediate-mass stars in the cloud. We argue that winds with a mass loss rate of about 10(-8) to 10(-6) M-circle dot yr(-1) are required to produce the observed shells. Our estimates indicate that the energy input rate from these stellar winds is similar to the turbulence dissipation rate. We conclude that in Perseus the total energy input from both collimated protostellar outflows and powerful spherical winds from young stars is sufficient to maintain the turbulence in the molecular cloud. Large-scale molecular line and IR continuum maps of a sample of clouds will help determine the frequency of this phenomenon in other star-forming regions.