Encyclopedia of Astrobiology

Living Edition
| Editors: Muriel Gargaud, William M. Irvine, Ricardo Amils, Henderson James Cleaves, Daniele Pinti, José Cernicharo Quintanilla, Michel Viso

Protostellar Envelope

  • Steven W. Stahler
Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-27833-4_1305-4


The mantle of gas surrounding a protostar is called the protostellar envelope. This material is freely collapsing onto the central star and its surrounding disk. The envelope is the densest portion of a molecular cloud core that went into gravitational collapse. Infalling, envelope material impacts the protostar and disk, creating a radiating shock front. The envelope gas contains solid dust grains, which absorb all optical and ultraviolet radiation from the star and accretion shock, reradiating it at infrared and longer wavelengths. Within about 1 AU from the star, the dust grains are thermally destroyed by sublimation. The dust photosphere (10 AU) is the radius at which the grains are so sparse that radiation streams passed them unimpeded. The emergent spectrum resembles a cold blackbody.

See Also


Bioorganic Chemistry Longe Wavelength Ultraviolet Radiation Shock Front Gravitational Collapse 
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Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  1. 1.Department of AstronomyUniversity of CaliforniaBerkeleyUSA