Simple estimate of the effect of a thick circumstellar dust shell on photospheric line profiles

Journal Article · Mon Jan 15 04:00:00 EST 1979 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/156763· OSTI ID:6272232

van Blerkom, D; Castor, J I

A star embedded in an optically thick dust shell may have a line spectrum that closely resembles the spectrum of some unobscured star--e.g., VY CMa (shrouded) and ..cap alpha.. Her (unshrouded). This implies that the surface temperatures of the two stars are nearly equal, but since one is subject to a back-warming effect, the distributions of temperature with depth in the respective atmospheres are dissimilar. We find that effective temperatures and absorption line strengths are reduced in shrouded stars below the values that obtain in their unshrouded counterparts. For models of VY CMa that yield grain temperatures at the inner boundary of the dust shell consistent with observation, the reduction in strength of a visible line is small (< or approx. =15%). Thus the spectral distribution of ..cap alpha.. Her may be used as an approximation to that of VY CMa before it is scattered by the dust, without the necessity of first correcting for back warming.

• Research Organization: Joint Institute for Laboratory Astrophysics, University of Colorado and National Bureau of Standards
• OSTI ID: 6272232
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 227:2; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics &amp; Cosmology-- Stars &amp; Quasi-Stellar
Radio &amp; X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABSORPTION SPECTRA
ATMOSPHERES
COSMIC DUST
DUSTS
ENERGY SPECTRA
GIANT STARS
INTERSTELLAR GRAINS
PARTICLES
SPECTRA
STARS
STELLAR ATMOSPHERES
STELLAR RADIATION
SUPERGIANT STARS
TEMPERATURE DISTRIBUTION