Dust condensation in dense interstellar clouds, and some related topics

Journal Article · Fri Sep 01 04:00:00 EDT 1978 · Sov. Astron. AJ (Engl. Transl.); (United States)

OSTI ID:6469565

Kolesnik, I G

The hypothesis is proposed that dust grains form in dense interstellar clouds. If the composition of a molecular cloud is determined by gas-phase reactions and the density n approx. = 10/sup 5/ cm/sup -3/, active dust condensation can occur. After approx. = 10/sup 7/ yr the grains will have a relative abundance epsilon/sub d/ = n/sub d//napprox. = 10/sup -9/ and their radius will rapidly grow to r/sub d/approx. = 10/sup -6/ cm. Since densities napprox. = 10/sup 5/ cm/sup -3/ are possible only in the central parts of massive clouds, subsequent dispersal throughout the cloud of dust formed in the nuclear region, together with the growth of the grains by adhesion of new particles, will yield the values epsilon/sub d/approx. = 10/sup -12/, r/sub d/approx. = 10/sup -5/ cm typical of the interstellar medium. Several implications of the hypothesis are discussed. The dense nuclei of massive clouds, cooling as dust forms there, will contract rapidly, fragmenting and collapsing to produce star clusters. The formation of H/sub 2/ molecules on the grains will serve as a source of strong infrared radiation at lambdaapprox. = 300 ..mu... For a cloud of 10/sup 18/ cm radius the infrared luminosity will reach Lapprox. = 3.5 x 10/sup -7/ n/sup 2/ L/sub sun/. The far-infrared radiation observed in several clouds could originate in this way, and act as an indicator for discovery of condensing clouds. The present hypothesis can explain the depletion of several elements that we observe in the interstellar gas. The genetic association between gas and dust in the Galaxy and the characteristic distribution of dust in the spiral arms of galaxies now find a natural interpretation.

• Research Organization: Central Astronomical Observatory, Academy of Sciences of the Ukrainian SSR, Kiev
• OSTI ID: 6469565
• Journal Information: Sov. Astron. AJ (Engl. Transl.); (United States), Journal Name: Sov. Astron. AJ (Engl. Transl.); (United States) Vol. 22:5; ISSN SAAJA
• Country of Publication: United States
• Language: English

Related Subjects

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640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CHEMICAL COMPOSITION
CONDENSATION NUCLEI
COSMIC DUST
COSMIC GASES
COSMIC RADIO SOURCES
CRYOGENIC FLUIDS
DATA
DATA FORMS
DENSITY
DUSTS
ELECTROMAGNETIC RADIATION
ELEMENTS
FLUIDS
GASES
H2 REGIONS
HYDROGEN
INFORMATION
INFRARED RADIATION
INTERSTELLAR GRAINS
ISOLATED VALUES
LUMINOSITY
NEBULAE
NONMETALS
NUMERICAL DATA
OPTICAL PROPERTIES
ORIGIN
PARTICLES
PHYSICAL PROPERTIES
RADIATIONS
STAR EVOLUTION
THEORETICAL DATA