3D Radiative Transfer Modelling and Virial Analysis of Starless Cores in the B10 Region of the Taurus Molecular Cloud

Abstract

Low-mass stars like our Sun begin their evolution within cold (10 K) and dense ($\sim 10^5$ cm${}^{-3}$) cores of gas and dust. The physical structure of starless cores is best probed by thermal emission of dust grains. We present a high resolution dust continuum study of the starless cores in the B10 region of the Taurus Molecular Cloud. New observations at 1.2mm and 2.0mm ($12^{"}$ and $18^{"}$ resolution) with the NIKA2 instrument on the IRAM 30m have probed the inner regions of 14 low-mass starless cores. We perform sophisticated 3D radiative transfer modelling for each of these cores through the radiative transfer framework $\text{pandora}$, which utilizes RADMC-3D. Model best-fits constrain each cores' central density, density slope, aspect ratio, opacity, and interstellar radiation field strength. These `typical' cores in B10 span central densities from $5\times 10^4-1\times 10^6$ cm${}^{-3}$, with a mean value of $2.6\times 10^5$ cm${}^{-3}$. We find the dust opacity laws assumed in the 3D modelling, as well as the estimates from $\text{Herschel}$, have dust emissivity indices, $\beta$'s, on the lower end of the distribution constrained directly from the NIKA2 maps, which averages to $\beta =2.01\pm 0.48$. From our 3D density structures and archival NH${}_3$ data, we perform a self-consistent virial analysis to assess each core's stability. Ignoring magnetic field contributions, we find 9 out of the 14 cores ($64\%$) are either in virial equilibrium or are bound by gravity and external pressure. To push the bounded cores back to equilibrium, an effective magnetic field difference of only $\sim 15\mu$G is needed.

Accepted to MNRAS. 19 pages, 20 figures

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