Correlating Infall with Deuterium Fractionation in Dense Cores

Abstract

We present a survey of HCO+ (3-2) observations pointed towards dense cores with previous measurements of N(N2D+)/N(N2H+). Of the 26 cores in this survey, five show the spectroscopic signature of outward motion, nine exhibit neither inward nor outward motion, eleven appear to be infalling, and one is not detected. We compare the degree of deuterium fractionation with infall velocities calculated from the HCO+ spectra and find that those cores with [D]/[H] > 0.1 are more likely to have the signature of inward motions than cores with smaller [D]/[H] ratios. Infall motions are also much more common in cores with masses exceeding their thermal Jeans masses. The fastest infall velocity measured belongs to one of the two protostellar cores in our survey, L1521F, and the observed motions are typically on the order of the sound speed.

Accepted to ApJ

References in corpus (12)

• MAMBO Mapping of Spitzer c2d Small Clouds and Cores
• The SCUBA Legacy Catalogue: Continuum Objects Detected by SCUBA
• The Mass Distribution and Lifetime of Prestellar Cores in Perseus, Serpens, and Ophiuchus
• Observing the gas temperature drop in the high-density nucleus of L 1544
• A SCUBA survey of Orion, the low-mass end of the core mass function
• Survey of ortho-H2D+(1_{1,0}-1_{1,1}) in dense cloud cores
• Depletion and low gas temperature in the L183 prestellar core : the N2H+ - N2D+ tool
• The N2D+/N2H+ ratio as an evolutionary tracer of Class 0 protostars
• Probing Inward Motions in Starless Cores Using The HCN J = 1-0 Hyperfine Transitions : A Pointing Survey Toward Central Regions
• TMC-1C: an accreting starless core
• The Effect of Noise in Dust Emission Maps on the Derivation of Column Density, Temperature and Emissivity Spectral Index
• Does a prestellar core always become protostellar? Tracing the evolution of cores from the prestellar to protostellar phase

Cited by in corpus (12)

• JCMT POL-2 and BISTRO Survey observations of magnetic fields in the L1689 molecular cloud
• Kinematics of a young low-mass star forming core: Understanding the evolutionary state of the First Core Candidate L1451-mm
• Prestellar core modeling in the presence of a filament - The dense heart of L1689B
• A large (~1 pc) contracting envelope around the prestellar core L1544
• Contraction Signatures Toward Dense Cores in the Perseus Molecular Cloud
• Radiative Transfer of HCN: Interpreting observations of hyperfine anomalies
• Infall/Expansion Velocities in the Low-Mass Dense Cores L492, L694-2, and L1521F: Dependence on Position and Molecular Tracer
• Icy molecule desorption in interstellar grain collisions
• Gas infalling motions in the envelopes of Very Low Luminosity Objects
• A Catalog of Molecular Clumps and Cores with Infall Signatures
• CLOVER: Convnet Line-fitting Of Velocities in Emission-line Regions
• Why do some cores remain starless ?