The initial conditions of isolated star formation - X. A suggested evolutionary diagram for prestellar cores

Abstract

We propose an evolutionary path for prestellar cores on the radius-mass diagram, which is analogous to stellar evolutionary paths on the Hertzsprung-Russell Diagram. Using James Clerk Maxwell Telescope (JCMT) observations of L1688 in the Ophiuchus star-forming complex, we analyse the HCO+ (J=4\rightarrow3) spectral line profiles of prestellar cores. We find that of the 58 cores observed, 14 show signs of infall in the form of a blue-asymmetric double-peaked line profile. These 14 cores all lie beyond the Jeans mass line for the region on a radius-mass plot. Furthermore another 10 cores showing tentative signs of infall, in their spectral line profile shapes, appear on or just over the Jeans mass line. We therefore propose the manner in which a prestellar core evolves across this diagram. We hypothesise that a core is formed in the low-mass, low-radius region of the plot. It then accretes quasistatically, increasing in both mass and radius. When it crosses the limit of gravitational instability it begins to collapse, decreasing in radius, towards the region of the diagram where protostellar cores are seen.

42 pages, 11 figures (+58 in appendix), Accepted for publication in MNRAS

References in corpus (9)

• The Mass Distribution and Lifetime of Prestellar Cores in Perseus, Serpens, and Ophiuchus
• A SCUBA survey of Orion, the low-mass end of the core mass function
• Hipparcos distances of Ophiuchus and Lupus cloud complexes
• Current Star Formation in the Ophiuchus and Perseus Molecular Clouds: Constraints and Comparisons from Unbiased Submillimeter and Mid-Infrared Surveys. II
• On the Distance to the Ophiuchus Star-Forming Region
• The Spitzer c2d Survey of Large, Nearby, Interstellar Clouds: VII. Ophiuchus Observed with MIPS
• The dust temperatures of the prestellar cores in the rho Oph main cloud and in other star forming regions: consequences for the core mass function
• The initial conditions of star formation VIII: an observational study of the Ophiuchus cloud L1688 and implications for the prestellar core mass function
• The initial conditions of isolated star formation - VII. Spitzer mapping of pre-stellar cores

Cited by in corpus (10)

• Global Hierarchical Collapse In Molecular Clouds. Towards a Comprehensive Scenario
• The JCMT Gould Belt Survey: First results from the SCUBA-2 observations of the Ophiuchus molecular cloud and a virial analysis of its prestellar core population
• First results from the Herschel Gould Belt Survey in Taurus
• The dense cores and filamentary structure of the molecular cloud in Corona Australis. Herschel SPIRE and PACS observations from the Herschel Gould Belt Survey
• The JCMT Legacy Survey of the Gould Belt: a molecular line study of the Ophiuchus molecular cloud
• Dense cores and star formation in the giant molecular cloud Vela~C
• Correlating Infall with Deuterium Fractionation in Dense Cores
• Contraction Signatures Toward Dense Cores in the Perseus Molecular Cloud
• On turbulent fragmentation and the origin of the stellar IMF
• Prestellar Cores in Turbulent Clouds: Properties of Critical Cores