Small Galactic H II regions. II. The molecular clouds and star formation

Journal Article · Sat Dec 01 04:00:00 EST 1990 · Astronomical Journal; (USA)

DOI:https://doi.org/10.1086/115647· OSTI ID:6104536

Hunter, D A; Thronson, Jr, H A; Wilton, C ^[1]

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1. Lowell Observatory, Flagstaff, AZ (USA) Wyoming Infrared Observatory, Laramie (USA)

CO maps of molecular clouds associated with 11 small Galactic H II regions are presented and compared with IR images obtained by IRAS. The molecular masses of the clouds are computed and compared with the masses of the stellar content. The mapped clouds have masses of 1000-60,000 solar and are typical of the more numerous, smaller Galactic molecular clouds. All of the clouds have recently made massive OB stars, and many have complex spatial and kinematic structures. The coincidence of IRAS sources and CO peaks suggests that many of the clouds have sites of star formation other than the optically visible H II region. Star-formation efficiencies are uncertain, with values for the clouds ranging from 0.02 to 0.6 with an average value of 0.2. There is no trend of the upper stellar mass limit with Galactic radius and with molecular cloud mass. 53 refs.

• OSTI ID: 6104536
• Journal Information: Astronomical Journal; (USA), Journal Name: Astronomical Journal; (USA) Vol. 100; ISSN 0004-6256; ISSN ANJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
COMPARATIVE EVALUATIONS
COSMIC GASES
COSMIC RADIO SOURCES
ELECTROMAGNETIC RADIATION
FLUIDS
GALAXIES
GASES
H2 REGIONS
INFRARED RADIATION
INTERSTELLAR SPACE
LIMITING VALUES
MASS
MILKY WAY
MOLECULES
OXIDES
OXYGEN COMPOUNDS
RADIATIONS
SPACE
STAR EVOLUTION