Star formation and galactic evolution. I. General expressions and applications to our galaxy

Journal Article · Sat Sep 15 04:00:00 EDT 1979 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/157330· OSTI ID:5731358

Kaufman, M

The study of galactic evolution involves three mechanisms for triggering star formation in interstellar clouds: (i) star formation triggered by a galactic spiral density wave, (ii) star formation triggered by shock waves from supernovae, and (iii) star formation triggered by an expanding H II region. Useful analytic approximations to the birthrate per unit mass are obtained by treating the efficiencies of these various mechanisms as time independent. In situations where shock waves from high-mass stars (either expanding H II regions or supernova explosions) are the only important star-forming mechanisms, the birthrate is exponential in time. This case is appropriate for the past evolution of an elliptical galaxy, nuclear bulge, or galactic halo. In the disk of a spiral galaxy where all three mechanisms operate, the birthrate consists of an exponential term plus a time-independent term. In both situations, the value of the time constant T in the exponential term is directly related to the efficiency of the shock waves from massive stars in initiating star formation.For our Galaxy, this simplified model is used to compute the radial distributions of young objects and low-mass stars in the disk, and the past and present birthrates in the solar-neighborhood shell.

• Research Organization: Department of Physics, The Ohio State University
• OSTI ID: 5731358
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 232:3; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
640105 -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMIC RADIO SOURCES
ERUPTIVE VARIABLE STARS
GALACTIC EVOLUTION
H2 REGIONS
INTERSTELLAR GRAINS
INTERSTELLAR SPACE
PARTICLES
SHOCK WAVES
SPACE
STAR EVOLUTION
STARS
SUPERNOVAE
VARIABLE STARS