Differences in chemical evolution between isolated and embedded prestellar cores by F. D. Priestley et al. on Thursday 24 November

Models of prestellar cores often assume that the cores are isolated from

their environment - material outside the core boundary plays no role in the

subsequent evolution. This is unlikely to be the case in reality, where cores

are located within hierarchically substructured molecular clouds. We

investigate the dynamical and chemical evolution of prestellar cores, modelled

as Bonnor-Ebert spheres, and show that the density of the ambient medium has a

large impact on the resulting chemical properties of the cores. Models embedded

in high-density, low-temperature surroundings have greatly enhanced abundances

of several molecules, such as CO and CS, compared to models with more diffuse

surroundings, corresponding to relatively isolated cores. The predicted

intensities and profile shapes of molecular lines are also affected. The

density of the ambient medium has a stronger effect on the chemical evolution

than whether the cores are initially in or out of equilibrium. This suggests

that the impact of environment cannot be neglected when modelling chemistry in

prestellar cores; the results of these models are highly sensitive to the

assumptions made about the core surroundings.

arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.12529v1