Ionized gas in active molecular cloud cores

Journal Article · Tue Feb 15 04:00:00 EST 1983 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/160723· OSTI ID:6268560

Bally, J; Predmore, R

Radio continuum sources at 5 GHz have been found to be associated with infrared objects in four molecular cloud cores. The sources S106 IR, CRL 961, NGC 2071 IRS 1, and NGC 2071 IRS 3 are ultracompact with angular diameters smaller than 1''. These radio continuum sources are buried in molecular clouds exhibiting energetic bipolar outflows in the vicinity of recent star formation. In S106 the flow is revealed by Doppler-shifted H..cap alpha.. emission from an extended biconical optical nebula, while in NGC 2071 and CRL 961 the flows are seen as high-velocity line wings on the 115 GHz carbon monoxide emission line. Extended radio emission is seen around S87 IRS 1 and in the optical nebula S106 which shows filamentary structure. The compact radio sources associated with S106 IR and CRL 961 may indicate the presence of massive, ionized stellar winds blowing from recently formed stars. The ratio of Br..cap alpha.. hydrogen recombination line flux to radio continuum flux is consistent with the wind model and inconsistent with an optically thin compact H II region. The mass-loss rate and the terminal velocity of the wind can be determined by two methods. If stellar winds drive the observed outflows, momentum conservation indicates that the wind parameters, averaged over the dynamic lifetimes of the outflows, are roughly dM/dtapprox.10/sup -5/ M/sub sun/ yr/sup -1/ and V/sub w/ approx.10/sup 3/ km s/sup -1/. Alternatively, a measurement of the Br..gamma.. hydrogen recombination linewidth gives the wind velocity directly. When combined with the ratio data, this method indicates that the current wind parameters are dM/dtapprox.10/sup -6/ M/sub sun/ yr/sup -1/ and V/sub w/ approx.10/sup 2/ km s/sup -1/. The discrepancy between the two determinations of the wind parameters suggests that either stellar winds are not entirely responsible for the observed large-scale outflows, or that if they are, the winds were either more energetic in the past or contain a large quantity of unobserved neutral gas.

• Research Organization: Bell Laboratories, Holmdel, New Jersey
• OSTI ID: 6268560
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 265:2; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMIC GASES
COSMIC RADIO SOURCES
FLUIDS
GASES
H2 REGIONS
INTERFEROMETRY
INTERSTELLAR GRAINS
IONIZATION
MAPS
NEBULAE
PARTICLES
PHOTOIONIZATION
STAR ACCRETION
STAR EVOLUTION
STELLAR WINDS