Wa. Feibelman et S. Johansson, C-IV AND O-VI TRANSITIONS IN THE REGION LAMBDA-LAMBDA-1100-2000 AND EXAMPLES FOUND IN IUE SPECTRA OF HOT STARS, The Astrophysical journal. Supplement series, 100(2), 1995, pp. 405-412
We present Ritz wavelengths for more than 130 transitions of C IV and
O VI in the range lambda lambda 1100-2000 and show examples of absorpt
ion features as seen in representative examples of high-dispersion IUE
spectra of very hot (similar to 100,000 K) nuclei of planetary nebula
e, white dwarfs, and PG 1159-type stars. The regions near He II lambda
1640 and interstellar Si II lambda 1260 are of particular interest be
cause they coincide with strong C IV and O VI transitions. O VI absorp
tions are detected in the IUE spectrum of the nucleus of the planetary
nebula NGC 7293, which suggests that this object may be a ''hybrid''
star with an H-rich atmosphere.