Molecular Line Profiles from a Core Forming in a Turbulent Cloud

Abstract

We calculate the evolution of molecular line profiles of HCO${}^{+}$ and C${}^{18}$O toward a dense core thatis forming inside a magnetized turbulent molecular cloud. Features of the profiles can be affected more significantly by coupled velocity and abundance structures in the outer region than those in the inner dense part of the core. The velocity structure at large radii is dominated by a turbulent flow nearby and accretion shocks onto the core, which resulting in the variation between inward and outward motions during the evolution of the core. The chemical abundance structure is significantly affected by the depletion of molecules in the central region with high density and low temperature. During the evolution of the core, the asymmetry of line profiles easily changes from blue to red, and vice versa. According to our study, the observed reversed (red) asymmetry toward some starless cores could be interpreted as an intrinsic result of outward motion in the outer region of a dense core, which is embedded in a turbulent environment and still grows in density at the center.

18pages, 4 figures, accepted for publication in Astrophysical Journal Letter

References in corpus (21)

• Control of star formation by supersonic turbulence
• Density, Velocity, and Magnetic Field Structure in Turbulent Molecular Cloud Models
• Dissipation in Compressible MHD Turbulence
• The Energy Dissipation Rate of Supersonic, Magnetohydrodynamic Turbulence in Molecular Clouds
• One-Point Probability Distribution Functions of Supersonic Turbulent Flows in Self-Gravitating Media
• A Survey for Infall Motions toward Starless Cores. II. $CS(2-1)$ and $N_2{H}^{+}(1-0)$ Mapping Observations
• Evolution of Chemistry and Molecular Line Profile during Protostellar Collapse
• Molecular ions in L1544. I. Kinematics
• New Protostellar Collapse Candidates: An HCO+ Survey of the Class 0 Sources
• The Lifetimes and Evolution of Molecular Cloud Cores
• The Formation of Self-Gravitating Cores in Turbulent Magnetized Clouds
• Consistency of Ambipolar Diffusion Models with Infall in the L1544 Protostellar Core
• Chemistry and Dynamics in Pre-Protostellar Cores
• How to Identify Pre-Protostellar Cores
• Oscillations of starless cores
• The Dynamical State fo the Starless Dense Core FeSt 1-457: A Pulsating Globule?
• The Dynamical State of the Starless Dense Core FeSt 1-457: A Pulsating Globule?
• Rotation of the pre-stellar core L1689B
• Using Chemistry to Unveil the Kinematics of Starless Cores: Complex Radial Motions in Barnard 68
• Molecular Line Observations of the Small Protostellar Group L1251B
• Comparisons of an Evolutionary Chemical Model with Other Models

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• Assessing molecular line diagnostics of triggered star formation using synthetic observations