Nucleation and stabilization of carbon-rich structures in interstellar media

Abstract

We study conditions under which carbon clusters of different sizes form and stabilize. {We describe an approach to equilibrium by simulating tenuous carbon gas dynamics to long times.} First, we use reactive molecular dynamics simulations to describe the nucleation of long chains, large clusters, and complex cage structures in carbon and hydrogen rich interstellar gas phases. We study how temperature, particle density, presence of hydrogen, and carbon inflow affect the nucleation of molecular moieties with different characteristics, in accordance with astrophysical conditions. We extend the simulations to densities which are orders of magnitude lower than current laboratory densities, to temperatures relevant to circumstellar environments of planetary nebulae, and to longtime (microsecond) formation timescales. We correlate cluster size distributions from dynamical simulations with thermodynamic equilibrium intuitions, where at low temperatures and gas densities, entropy plays a significant role.

5 figures (accepted for ApJ)

References in corpus (2)

• Formation of methyl formate and other organic species in the warm-up phase of hot molecular cores
• Discovery of Interstellar Propylene (CH_2CHCH_3): Missing Links in Interstellar Gas-Phase Chemistry

Cited by in corpus (6)

• Top-down formation of fullerenes in the interstellar medium
• First Multimessenger Observations of a Neutron Star Merger
• Can Neutron-Star Mergers Explain the r-process Enrichment in Globular Clusters?
• Formation of interstellar complex polycyclic aromatic hydrocarbons: Insights from molecular dynamics simulations of dehydrogenated benzene
• Simulating the structural diversity of carbon clusters across the planar to fullerene transition
• Evolution of Fullerenes in Circumstellar Envelopes by Carbon Condensation: Insights from Reactive Molecular Dynamics Simulations