Interpretation of the spectrum of the Red Rectangle

Journal Article · Fri Apr 01 04:00:00 EST 1977 · Publ. Astron. Soc. Pac.; (United States)

DOI:https://doi.org/10.1086/130089· OSTI ID:7211760

Greenstein, J L; Oke, J B

The strong infrared source centered on HD 44179 has been observed with the multichannel spectrophotometer from 0.35..mu.. to 1.1..mu... The stellar spectrum is anomalous. If we fit a model atmosphere suitable for a late B giant it must have a circumstellar shell. If it is a low-gravity F bright giant its reported slit spectrum suggests unusual composition. The total luminosity is high, from the far infrared fluxes. The nebula, the Red Rectangle, has been observed without stellar contamination. Largely of the reflection type, it is unusual in being considerably redder than the star. The surface brightness is interpreted from the first-order and exact theory of scattering by grains in an optically thick nebula, with the star in front. The color is ascribed to the variation of the albedo with frequency. An unusual feature is a broad upward rise in brightness of the nebula, centered at 6600 A, requiring a four-fold increase in albedo over a region 1700 A wide (full width at half maximum). The albedo is so high that the most favorable geometry must be assumed; otherwise the red maximum might require fluorescence. If the high reflectivity in the red is a feature of the dust grains, they have composition quite different from other reflection nebulae, meteorites, or planets.

• Research Organization: California Inst. of Tech., Pasadena
• OSTI ID: 7211760
• Journal Information: Publ. Astron. Soc. Pac.; (United States), Journal Name: Publ. Astron. Soc. Pac.; (United States) Vol. 89:528; ISSN PASPA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMIC DUST
CRYSTAL STRUCTURE
DUSTS
ELECTROMAGNETIC RADIATION
GRAIN SIZE
INFRARED RADIATION
LUMINOSITY
MATHEMATICAL MODELS
MICROSTRUCTURE
NEBULAE
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIATIONS
SIZE
STAR MODELS