EPoS Contribution
EPoS Contribution
Modeling the First Hydrostatic Core Candidates Barnard 1b-N and 1b-S

Hao-Yuan Duan
NTHU, Hsinchu, TW
Probing the collapse process from a prestellar core to a Class 0 protostar is a key to understand the earliest stage of low-mass star formation. Theories proposed that a First Hydrostatic Core (FHC) would form at this stage, which has a size of ∼ 5 AU, a mass of ∼ 0.05 Msun, and temperature between 100 - 1000K. However, FHCs are difficult to observe because they are small, compact, embedded, and short lived. Several FHC candidates have been proposed, and they are characterized by very cold SEDs with temperature ranging from ∼ 10 - 30K, very low luminosities (< 0.1 - 0.25 Lsun), and most of them are found to have slow, poorly-collimated outflows. We have explored the physical properties of two FHC candidates, B1-bN and B1-bS, by fitting interferometric data with simulated synthesis images of two first cores. We produce the images based on a simple model that contains a single hot compact first core-like component at the center surrounded by a large-scale, cold and dusty envelope. Our results show that both cores can be well described with a hot compact object with a temperature of 200 - 800K and a size of 2 - 8 AU, and B1-bS is slightly more evolved than B1-bN. These values agree well with theoretical predictions for an FHC. The identification of more FHCs will make great strides in our understanding of star formation. agrees well with theoretical predictions for an FHC suggest that the two sources are extremely young objects, each with a hot compact component that agrees well with theoretical predictions for an FHC and B1-bS is slightly more evolved than B1-bN. The identification of FHCs will make great strides in our understanding of star formation.
Caption: Procedure of creating synthesized images of our first core model, and the best fitting result for B1-bN and B1-bS.
Collaborators:
S-P. Lai, NTHU, TW
Suggested Session: Cores