COLLAPSE OF MOLECULAR CLOUD CORES WITH RADIATION TRANSFER: FORMATION OF MASSIVE STARS BY ACCRETION
- Centro de Fisica, Instituto Venezolano de Investigaciones CientIficas, IVIC, Apartado 21827, Caracas 1020A (Venezuela, Bolivarian Republic of)
- Dipartimento di Fisica 'G. Galilei', Universita di Padova, Via Marzolo 8 35131 Padova (Italy)
Most early radiative transfer calculations of protostellar collapse have suggested an upper limit of approx40 M{sub sun} for the final stellar mass before radiation pressure can exceed the star's gravitational pull and halt the accretion. Here we perform further collapse calculations, using frequency-dependent radiation transfer coupled to a frequency-dependent dust model that includes amorphous carbon particles, silicates, and ice-coated silicates. The models start from pressure-bounded, logatropic spheres of mass between 5 M{sub sun} and 150 M{sub sun} with an initial nonsingular density profile. We find that in a logatrope the infall is never reversed by the radiative forces on the dust and that stars with masses approx>100 M{sub sun} may form by continued accretion. Compared to previous models that start the collapse with a rho propor to r{sup -2} density configuration, our calculations result in higher accretion times and lower average accretion rates with peak values of approx5.8 x 10{sup -5} M{sub sun} yr{sup -1}. The radii and bolometric luminosities of the produced massive stars (approx>90 M{sub sun}) are in good agreement with the figures reported for detected stars with initial masses in excess of 100 M{sub sun}. The spectral energy distribution from the stellar photosphere reproduces the observed fluxes for hot molecular cores with peaks of emission from mid- to near-infrared.
- OSTI ID:
- 21392560
- Journal Information:
- Astrophysical Journal, Vol. 707, Issue 2; Other Information: DOI: 10.1088/0004-637X/707/2/1438; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COSMOLOGY AND ASTRONOMY
ACCRETION DISKS
BOLOMETERS
CARBON
DUSTS
EMISSION
ENERGY SPECTRA
FREQUENCY DEPENDENCE
ICE
LUMINOSITY
MASS
PARTICLES
PHOTOSPHERE
RADIANT HEAT TRANSFER
RADIATION PRESSURE
SILICATES
STARS
ATMOSPHERES
ELEMENTS
ENERGY TRANSFER
HEAT TRANSFER
MEASURING INSTRUMENTS
NONMETALS
OPTICAL PROPERTIES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SILICON COMPOUNDS
SOLAR ATMOSPHERE
SPECTRA
STELLAR ATMOSPHERES