Ten-micron observations of bright circumstellar shells - spectral properties and a search for extended emission
A 9-14 micron spectra are obtained for several bright long-period variable stars, using novel instrumentation comprising a mosaic detector array and a prism slit spectrometer. Three of the stars are carbon rich and have SiC feature emission. The remaining five are oxygen rich; three exhibit pronounced silicate emission. Agreement is found in the SiC equivalent widths for the three carbon stars observed here and during the 1983 flight of the IRAS low-resolution spectrometer. Two stars with silicate feature emission observed at both epochs, IRAS + 10420 and mu Cep, show pronounced variation in the equivalent widths of these features. Continuum variations are observed exceeding the photometric levels of uncertainty for either instrument for the carbon star V Cyg with which correlate well with visible light curves. None of the circumstellar shells of these stars were fully resolved; only IRC + 10420 may be partially resolved. The observed upper limits on surface brightness of dust associated with molecular outflows from IRC + 10216 are compatible with calculated lower limits, yielding no additional constrains on the depressed dust emission suggested by far-infrared detections of the outflow material.
- Research Organization:
- Air Force Geophysics Lab., Hanscom AFB, MA (USA)
- OSTI ID:
- 5994899
- Report Number(s):
- AD-A-227725/9/XAB; GL-TR-90-0250
- Resource Relation:
- Other Information: Pub. in Publications of the Astronomical Society of the Pacific, Vol. 101, No. 646, 1140-1150(Dec 1989)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
VARIABLE STARS
INFRARED SPECTRA
BRIGHTNESS
CARBON STARS
CHEMICAL COMPOSITION
COSMIC DUST
EMISSION SPECTRA
FAR INFRARED RADIATION
GAS FLOW
INFRARED RADIATION
LIMITING VALUES
MASS TRANSFER
OXYGEN
PHOTOMETRY
RESOLUTION
SILICATES
SPECTROMETERS
SPECTROSCOPY
STELLAR ATMOSPHERES
SURFACES
VARIATIONS
ATMOSPHERES
DUSTS
ELECTROMAGNETIC RADIATION
ELEMENTS
FLUID FLOW
MAIN SEQUENCE STARS
MEASURING INSTRUMENTS
NONMETALS
OPTICAL PROPERTIES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RADIATIONS
SILICON COMPOUNDS
SPECTRA
STARS
640102* - Astrophysics & Cosmology- Stars & Quasi-Stellar
Radio & X-Ray Sources