Vol 22, No 9

A Catalog of Molecular Clumps and Cores with Infall Signatures

Shuling Yu (于书岭), Zhibo Jiang (江治波), Yang Yang (杨旸), Zhiwei Chen (陈志维), and Haoran Feng (冯浩然)


The research of infall motion is a common means to study molecular cloud dynamics and the early process of star formation. Many works had been done in-depth research on infall. We searched the literature related to infall study of molecular cloud since 1994, summarized the infall sources identified by the authors. A total of 456 infall sources are cataloged. We classify them into high-mass and low-mass sources, in which the high-mass sources are divided into three evolutionary stages: prestellar, protostellar and H II region. We divide the sources into clumps and cores according to their sizes. The H2 column density values range from 1.21 × 1021 to 9.75 × 1024 cm−2, with a median value of 4.17 × 1022 cm−2. The H2 column densities of high-mass and low-mass sources are significantly separated. The median value of infall velocity for high-mass clumps is 1.12 km s−1, and the infall velocities of lowmass cores are virtually all less than 0.5 km s−1. There is no obvious difference between different stages of evolution. The mass infall rates of low-mass cores are between 10−7 and 10−4 \(M_{\odot} yr^{−1}\), and those of high-mass clumps are between 10−4 and 10−1 \(M_{\odot} yr^{−1}\) with only one exception. We do not find that the mass infall rates vary with evolutionary stages.


stars: formation – ISM: molecules – ISM: kinematics and dynamics – radio lines: ISM

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