Using Chemistry to Unveil the Kinematics of Starless Cores: Complex Radial Motions in Barnard 68

Abstract

We present observations of 13CO, C18O, HCO+, H13CO+, DCO+ and N2H+ line emission towards the Barnard 68 starless core. The line profiles are interpreted using a chemical network coupled with a radiative transfer code in order to reconstruct the radial velocity profile of the core. Our observations and modeling indicate the presence of complex radial motions, with the inward motions in the outer layers of the core but outward motions in the inner part, suggesting radial oscillations. The presence of such oscillation would imply that B68 is relatively old, typically one order of magnitude older than the age inferred from its chemical evolution and statistical core lifetimes. Our study demonstrates that chemistry can be used as a tool to constrain the radial velocity profiles of starless cores.

12 pages, 3 figures, to appear in the Astrophysical Journal Letters

References in corpus (8)

• Observing the gas temperature drop in the high-density nucleus of L 1544
• On the internal structure of starless cores. II. A molecular survey of L1498 and L1517B
• The Thermal Structure of Gas in Pre-Stellar Cores: A Case Study of Barnard 68
• The Ionization Fraction of Barnard 68: Implications for Star and Planet Formation
• Oscillations of starless cores
• The Dynamical State of the Starless Dense Core FeSt 1-457: A Pulsating Globule?
• The Dynamical State fo the Starless Dense Core FeSt 1-457: A Pulsating Globule?
• Oscillations in the stable starless core Barnard 68

Cited by in corpus (5)

• The Different Structures of the Two Classes of Starless Cores
• The Earliest Phases of Star formation observed with Herschel (EPoS): The dust temperature and density distributions of B68
• Molecular Line Profiles from a Core Forming in a Turbulent Cloud
• Core formation via filament fragmentation and the impact of ambient pressure on it
• Why do some cores remain starless ?