Sign on
ADS Classic is now deprecated. It will be completely retired in October 2019. Please redirect your searches to the new ADS modern form or the classic form. More info can be found on our blog.

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Full Refereed Journal Article (PDF/Postscript)
· Full Refereed Scanned Article (GIF)
· References in the article
· Citations to the Article (100) (Citation History)
· Refereed Citations to the Article
· SIMBAD Objects (1)
· Associated Articles
· Also-Read Articles (Reads History)
· Translate This Page
Collapse and fragmentation of molecular cloud cores. 2: Collapse induced by stellar shock waves
Boss, Alan P.
AA(Carnegie Institute of Washington, Washington, DC, US)
Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 439, no. 1, p. 224-236 (ApJ Homepage)
Publication Date:
NASA/STI Keywords:
Astronomical Models, Collapse, Molecular Clouds, Shock Waves, Star Formation, Computerized Simulation, Hydrodynamics, Numerical Analysis, Thermodynamics, Three Dimensional Models
Bibliographic Code:


The standard scenario for low-mass star formation involves 'inside-out' collapse of a dense molecular cloud core following loss of magnetic field support through ambipolar diffusion. However, isotopic anomalies in presolar grains and meteoritical inclusions imply that the collapse of the presolar cloud may have been triggered by a stellar shock wave. This paper explores 'outside-in' collapse, that is, protostellar collapse initiated directly by the compression of quiescent dense cloud cores impacted by relatively slow stellar shock waves. A second-order accurate, gravitational hydrodynamics code has been used to study both the spherically symmetrical and three-dimensional evolution of initially centrally condensed, isothermal, self-gravitating, solar-mass cloud cores that are struck by stellar shock waves with velocities up to 25 km/s and postshock temperatures of 10 to 10,000 K. The models show that such mild shock waves do not completely shred and destroy the cloud, and that the dynamical ram pressure can compress the cloud to the verge of self-gravitational collapse. However, compression caused by a high postshock temperature is a considerably more effective means of inducing collapse. Shock-induced collapse produces high initial mass accretion rates (greater than 10-4 solar mass/yr in a solar-mass cloud) that decline rapidly to much lower values, depending on the presence (approximately 10-6 solar mass/yr) or absence (approximately 10-8 to 10-7 solar mass/yr) of an infinite reservoir of mass. Stellar mass accretion rates approximately 10-7 solar mass/yr have been previously inferred from the luminosities of T Tauri stars; balanced mass accretion (stellar rate = envelope rate) at approximately 10-7 solar mass/yr could then be possible if accretion occurs from a finite mass reservoir. Fluid tracers are used to determine what fraction of the stellar shock material is incorporated into the resulting protostellar object and disk; roughly half the impinging material is injected into the collapsing cloud core when there is a high postshock temperature. The models are consistent with a scenario where an AGB star wind triggered the collapse of the presolar cloud while injecting about 0.01 solar mass of matter derived from the AGB star envelope, as has been separately inferred on the basis of nucleosynthesis calculations.

Associated Articles

Part  1     Part  2     Part  3     Part  4     Part  5     Part  6     Part  7     Part  8     Part  9     Part 10    

Printing Options

Send high resolution image to Level 2 Postscript Printer
Send low resolution image to Level 2 Postscript Printer
Send low resolution image to Level 1 Postscript Printer
Get high resolution PDF image
Get low resolution PDF
Send 300 dpi image to PCL Printer
Send 150 dpi image to PCL Printer

More Article Retrieval Options

HELP for Article Retrieval

Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)

Find Similar Abstracts:

Use: Authors
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
arXiv e-prints