Modeling Two First Hydrostatic Core Candidates Barnard 1b-N and 1b-S

Abstract A first hydrostatic core (FHC) is proposed to form after the initial collapse of a prestellar core, as seed Class 0 protostar. FHCs are difficult observe because they small, compact, embedded, and short lived. In this work, we explored physical properties two well-known FHC candidates, B1-bN B1-bS, by comparing interferometric data from Submillimeter Array (SMA) 1.1 1.3 mm Atacama Large Millimeter/submillimeter (ALMA) 870 μ m observations with simulated synthesis images sources. The based on simple model containing single, hot compact first-core-like component at center surrounded large-scale, cold dusty envelope described broken power-law density distribution an index, α . Our results show that components B1-bS can be temperatures ∼500 K size ∼4 au, which in agreement theoretical predictions FHC. If inside radii fixed −1.5, find ∼−2.9 ∼−3.3 outside for respectively, consistent calculations collapsing, bounded previous observations. Comparing temperature profiles sources radiation-hydrodynamic simulations FHC, both lie close to, but before, second stage. We suggest may have started collapsing process earlier compared B1-bN, since larger discontinuity point found its profile.