Astronomy and Astrophysics – Astrophysics
Scientific paper
Jun 1982
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1982apj...257..672w&link_type=abstract
Astrophysical Journal, Part 1, vol. 257, June 15, 1982, p. 672-685.
Astronomy and Astrophysics
Astrophysics
97
Abundance, Balmer Series, Emission Spectra, Helium, Stellar Spectrophotometry, Variable Stars, Dwarf Novae, Optical Thickness, Stellar Evolution, Stellar Mass Accretion, Stellar Models, Stellar Structure, Temporal Resolution, Thermodynamic Equilibrium, White Dwarf Stars
Scientific paper
Time-resolved spectroscopy of a sample of eclipsing cataclysmic variables indicates that the He I emission lines are formed with the Balmer lines in the outer regions of the accretion disk. Additional observations of lower inclination noneclipsing systems demonstrate that the He I emission is frequently characterized by relatively high singlet to triplet intensity ratios and an inverted line decrement, an unusual situation which can be explained in terms of emission from an optically thick (in the lines) region in local thermodynamic equilibrium. Calculations of steady state accretion disk structure show that the observed characteristics of the He I and H I lines can be reproduced in normal disk models, but only if the helium abundance is assumed to be very high, i.e., He/H greater than approximately 100 by number. Enhanced helium abundances are thus implied for some cataclysmic variable secondaries, suggesting that they are either highly evolved cores or that they have an outer layer of processed material which was accreted from the white dwarf during earlier evolution of the system.
Ferguson Donald H.
Williams Robert E.
No associations
LandOfFree
He I line emission and the helium abundance in cataclysmic variables does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with He I line emission and the helium abundance in cataclysmic variables, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and He I line emission and the helium abundance in cataclysmic variables will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1351681