SIMBAD references

We present a near-infrared extinction study of nine dense cores at evolutionary stages between starless and Class I. Our results show that the density structure of all but one observed core can be modeled with a single power law ρ {vprop} r^p between ∼0.2R-R of the cores. The starless cores in our sample show two different types of density structures, one follows p ∼ -1.0 and the other follows p ∼ -2.5, while the protostellar cores all have p ∼ -2.5. The similarity between the prestellar cores with p ∼ -2.5 and protostellar cores implies that those prestellar cores could be evolving toward the protostellar stage. The slope of p ∼ -2.5 is steeper than that of an singular isothermal sphere, which may be interpreted with the evolutionary model of cores with finite mass.