Far and extreme-ultraviolet spectrophotometry of hot white dwarfs - Prospects for the determination of the He/H ratio in DA stars

Details Far and extreme-ultraviolet spectrophotometry of hot white dwarfs - Prospects for the determination of the He/H ratio in DA stars Far and extreme-ultraviolet spectrophotometry of hot white dwarfs - Prospects for the determination of the He/H ratio in DA stars

Dec 1984

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1984pasp...96..981w&link_type=abstract

Astronomical Society of the Pacific, Publications (ISSN 0004-6280), vol. 96, Dec. 1984, p. 981-987. Research supported by the Na

Astronomy and Astrophysics

Astronomy

9

Extreme Ultraviolet Radiation, Far Ultraviolet Radiation, Helium Hydrogen Atmospheres, Stellar Spectrophotometry, Ultraviolet Astronomy, White Dwarf Stars, A Stars, Abundance, Helium, Hot Stars, Hydrogen, Iue, Stellar Models, Visible Spectrum, Wavelengths

Scientific paper

The various spectroscopic methods currently available to determine the He/H ratio in hot DA white dwarfs are compared and contrasted. The observation of the optical He II λ4686 line, as well as that of the λ1640 line with the low-dispersion IUE camera, can only be wsed to determine the helium abundance for log (He/H) > -3. Low-resolution (λ/Δλ ˜ 20) rocket-borne extreme ultraviolet spectrophotometry, such as that performed on HZ 43, is more sensitive to the abundance ratio, but only through the strength of the He II edge at 227 λ. We contrast these results with those expected from the Faint Object Spectrograph on the Space Telescope and from the Far Ultraviolet Spectroscopic Explorer. We show, in particular, that medium-resolution (λ/Δλ ˜ 100) extreme ultraviolet spectrophotometry remains sensitive to the helium abundance-through the He II resonance series-down to trace levels of log (He/H) ≍ -8. Measurements of hot DA white dwarfs in that wavelength range are thus expected to enhance considerably our understanding of the efficiency of element diffusion, and of competing processes, in the photospheres of these stars.

Affiliated with

Also associated with

No associations

Rating

Far and extreme-ultraviolet spectrophotometry of hot white dwarfs - Prospects for the determination of the He/H ratio in DA stars 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 Far and extreme-ultraviolet spectrophotometry of hot white dwarfs - Prospects for the determination of the He/H ratio in DA stars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Far and extreme-ultraviolet spectrophotometry of hot white dwarfs - Prospects for the determination of the He/H ratio in DA stars will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-739175