Properties of Contracting Massive Protostellar Cores

Studies of the structure and kinematics of cores associated with the regions of massive star and star cluster formation are necessary for constructing scenario for the evolution of these objects. We analyzed spectral maps of massive cores G012.418+00.506, G326.472+00.888, G328.567–00.535, G335.586–00.289 and G343.127–00.063 from the MALT90 survey in the HCO+(1–0) and H13CO+(1–0) lines. The cores are at different stages of evolution and have signs of contraction. By fitting spectral maps calculated within the framework of the spherically-symmetric model into the observed ones, the parameters of the density, turbulent velocity, and contraction velocity radial profiles are calculated. The power-law index of the density decay with distance from the center varies in the range of ∼1.5–2.8, the lowest value is obtained for the core G326.472+00.888 without internal sources. The contraction velocity in all the cores depends weakly on the distance from the center, decreasing with the index ∼0.1, which differs from the free-fall regime. For the cores G328.567–00.535 and G335.586–00.289 there are indications of rotation. Analysis of the 13CO(2–1) data from the SEDIGISM survey for the G012.418+00.506, G335.586–00.289 and G343.127–00.063 regions has revealed motions from surrounding gas to the cores. The results obtained indicate that the massive cores under consideration interact with their environment and are apparently in a state of global collapse.