Spectrophotometry of filaments in the Crab Nebula
Photoelectric spectrophotometry of filaments in the Crab Nebula has been obtained with the Lick Observatory 3 m reflector, and intensities for a number of emission lines between 3400 and 7400 A are presented. Temperatures determined from (O III) lines range from 11,400 to 16,100 K, while the low-ionization species N/sup +/, O/sup +/, and S/sup +/ indicate lower temperatures near 8000 K. Abundance calculations suggest that oxygen, nitrogen, and neon, relative to hydrogen, are within a factor of 10 of what is considered normal. Sulfur appears to be overabundant, but this could be a result of the ionization structure rather than a true abundance effect. Helium lines yield apparent abundances in the range 0.46 to 0.87 relative to hydrogen by number and are consistent with the value N (He)/N (H) approx. =1 if allowance is made for neutral helium in the ionized hydrogen regions. There is little doubt that helium is considerably overabundant, and it is likely that the Crab Nebula contains over 1 M/sub sun/ of helium.
- Research Organization:
- Lick Observatory
- OSTI ID:
- 5078661
- Journal Information:
- Astrophys. J.; (United States), Vol. 220:2
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
CRAB NEBULA
CHEMICAL COMPOSITION
ENERGY SPECTRA
ABUNDANCE
COSMOCHEMISTRY
HELIUM IONS
IONIZATION
NITROGEN IONS
OXYGEN IONS
PLANETARY NEBULAE
STAR MODELS
SULFUR IONS
SYNCHROTRON RADIATION
ATOMIC IONS
BREMSSTRAHLUNG
CHARGED PARTICLES
CHEMISTRY
COSMIC RADIO SOURCES
ELECTROMAGNETIC RADIATION
IONS
MATHEMATICAL MODELS
NEBULAE
RADIATIONS
SPECTRA
SUPERNOVA REMNANTS
640102* - Astrophysics & Cosmology- Stars & Quasi-Stellar
Radio & X-Ray Sources