SIMBAD references

2014ApJ...789...50H - Astrophys. J., 789, 50 (2014/July-1)

Two extreme young objects in Barnard 1-b.


Abstract (from CDS):

Two submillimeter/millimeter sources in the Barnard 1b (B1-b) core, B1-bN and B1-bS, have been studied in dust continuum, H13CO+ J = 1-0, CO J = 2-1, 13CO J = 2-1, and C18O J = 2-1. The spectral energy distributions of these sources from the mid-IR to 7 mm are characterized by very cold temperatures of Tdust< 20 K and low bolometric luminosities of 0.15-0.31 L. The internal luminosities of B1-bN and B1-bS are estimated to be <0.01-0.03 L and ∼0.1-0.2 L, respectively. Millimeter interferometric observations have shown that these sources have already formed central compact objects of ∼100 AU sizes. Both B1-bN and B1-bS are driving the CO outflows with low characteristic velocities of ∼2-4 km/s. The fractional abundance of H13CO+ at the positions of B1-bN and B1-bS is lower than the canonical value by a factor of four to eight. This implies that a significant fraction of CO is depleted onto dust grains in the dense gas surrounding these sources. The observed physical and chemical properties suggest that B1-bN and B1-bS are in an earlier evolutionary stage than most of the known class 0 protostars. In particular, the properties of B1-bN agree with those of the first hydrostatic core predicted by the MHD simulations. The CO outflow was also detected in the mid-IR source located at ∼15'' from B1-bS. Since the dust continuum emission was not detected in this source, the circumstellar material surrounding this source is less than 0.01 M. It is likely that the envelope of this source was dissipated by the outflow from the protostar that is located to the southwest of B1-b.

Abstract Copyright:

Journal keyword(s): stars: formation - stars: individual: (B1-bN, B1-bS)

Status at CDS:  

Simbad objects: 32

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