Analysis of dust grain properties in two star-forming regions through comparison of theoretical models to observations

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1987

OSTI ID:6935246

Pendleton, Y J

Infrared reflection nebulae in two regions of star formation, Orion Molecular Cloud-2 and Cepheus A, were studied both observationally and theoretically. An analytical formula is derived that describes the scattered light intensity under the assumption of single scattering. The grain components, graphite, silicate, and ice, determined the scattering and absorption properties of the dust. Mie theory was used to study the behavior of a Mathis, Rumpl, and Nordsieck (1977) grain-size distribution of particles, which ranged in radius from 0.005 less than or equal to a less than or equal to 0.3 and 0.05 less than or equal to a less than or equal to 0.5 ..mu..m, called the standard and non-standard cases, respectively. Variations of the optical depth of the nebula, the scattering angle, grain sizes, and the effect of ice mantles were investigated. The models show that it is possible to explain the continuum flux level and shape of the near-infrared scattered light with illumination by a near-infrared source and a grain-size distribution of graphite and silicate grains. The 3.1-..mu..m feature seen in the spectra of the reflected light was reproduced by coating the grains in the nebula with water ice.

• Research Organization: California Univ., Santa Cruz (USA)
• OSTI ID: 6935246
• 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
COSMIC DUST
DUSTS
ELECTROMAGNETIC RADIATION
INFRARED RADIATION
INTERSTELLAR GRAINS
LIGHT SCATTERING
MATHEMATICAL MODELS
NEAR INFRARED RADIATION
NEBULAE
PARTICLES
RADIATIONS
SCATTERING
STAR EVOLUTION
STAR MODELS