Observations that link infrared cirrus and ultraviolet extinction

Journal Article · Mon Jul 01 04:00:00 EDT 1991 · Astrophysical Journal; (United States)

DOI:https://doi.org/10.1086/170178· OSTI ID:5226068

Hackwell, J A; Hecht, J H; Tapia, M ^[1]

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1. Aerospace Corp., Los Angeles, CA (USA)

Results are presented of UV extinction measurements of 17 stars in the open cluster IC 4665 and of four stars in the open cluster NGC 1647, showing that the UV extinctions of the two clusters stars have different properties. Whereas the stars in NGC 1647 cluster are typical of general interstellar space, the stars in IC 4665 have a small 'linear' term which is typical of stars found near regions of active star formation. Using data from the IRAS satellite to study the emission by the 'infrared cirrus' for each of the regions and to measure the I(60-micron)/I(100-micron) ratio for the two regions, it was found that, when the linear term component is present, it dominates the 100-micron cirrus emission. When it is absent, the 100-micron emission is from the relatively hot particles that are responsible for the 60-micron emission. It is suggested that the 60-micron emitters are small carbonaceous grains that are major contributors to all parts of the UV extinction except the linear term. 59 refs.

• OSTI ID: 5226068
• Journal Information: Astrophysical Journal; (United States), Journal Name: Astrophysical Journal; (United States) Vol. 375; ISSN ASJOA; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABSORPTION
CARBONACEOUS MATERIALS
ELECTROMAGNETIC RADIATION
EMISSION SPECTRA
INTERSTELLAR GRAINS
INTERSTELLAR SPACE
MATERIALS
PARTICLES
RADIATIONS
SPACE
SPECTRA
STAR CLUSTERS
STAR EVOLUTION
STELLAR RADIATION
ULTRAVIOLET RADIATION