Search Publications
Metal abundances in the hot DA white dwarfs Wolf 1346 and Feige 24.
Wesemael, F.; Henry, R. B. C.; Shipman, H. L.
Photospheric metal lines observed in high-dispersion IUE spectra of the hot DA white dwarfs Wolf 1346 and Feige 24 are analyzed with detailed model synthetic spectra in order to derive metal abundances in the two stars. The IUE images used in the analysis are first discussed together with the theoretical framework, an extensive set of metal line p…
Characteristics of the Fe II and C II emission in high-resolution IUEspectra (2300-3000 A ) of alpha Orionis.
Carpenter, K. G.
A study is presented of Fe II and C II emission features in the 2300-3000 A region of four high-resolution IUE spectra of Alpha Ori obtained during the period 1978 April-1982 November. A set of 42 unmutilated, unblended Fe II lines of multiplets UV 1-3, 32-33, 35-36, and 60-64 and the C II (UV 0.01) intercombination lines have been identified and …
IUE observations of the high-velocity symbiotic star AG Draconis. II.The spectral variations during 1979-1983.
Altamore, A.; Baratta, G. B.; Friedjung, M. +2 more
High quality IUE spectra of AG Dra gathered during 1979-81 were examined in concert with data taken at VILSPA. Visual bursts were detected in 1980 and 1983 and were associated with order of magnitude changes in the UV continuum and emission lines. Variability was persistent in the UV and He II lines after the bursts while the C IV line displayed s…
The high-ionization and excited-state interstellar lines in the Carina Nebula : a giant HII region in absorption.
Walborn, N. R.; Heckathorn, J. N.; Hesser, J. E.
The dominant component of the highly ionized and excited-state interstellar species seen in the ultraviolet toward stars within the Carina Nebula has been found to have a heliocentric radial velocity of about -30 km/s. This velocity is known to correspond to the near edge of the expanding H II region, as shown by the double optical nebular emissio…
Absolute spectrophotometry of Wolf-rayet stars from 1200 to 7000 A : a cautionary tale.
Conti, P. S.; Garmany, C. D.; Massey, P.
It is demonstrated that absolute spectrophotometry of the continua of Wolf-Rayet stars may be obtained over the wavelength range 1200-7000 A using IUE and optical measurements. It is shown that the application of a 'standard' reddening law to the observed data gives spurious results in many cases. Additional UV extinction is apparently necessary a…
The origin of low-velocity absorption components in the MG II resonance lines of hybrid-chromosphere stars.
Linsky, J. L.; Brown, A.; Drake, S. A.
It is argued that the low-velocity absorption features seen in the Mg II resonance lines of seven confirmed and three probable hybrid-chromosphere stars are interstellar rather than circumstellar in origin. From a comparison of radial velocities based on all available spectra in the International Ultraviolet Explorer (IUE) archives with estimates …
Two multifrequency observations of 3C 371.
Bruhweiler, F. C.; Miller, H. R.; Worrall, D. M. +14 more
We present observations of 3C 37t, made at frequencies from the radio to the ultraviolet, which were coordinated during two short time intervals separated by 3 months. We also present 1 keV X-ray flux densities measured at a different time. The multifrequency measurements indicate spectral steepening at visual wavelengths, and that an extrapolatio…
Ultraviolet flare on lambda Andromedae.
Dupree, A. K.; Guinan, E. F.; Baliunas, S. L.
On November 5, 6, 1982, a luminous, flarelike brightening of the ultraviolet emissions was observed with IUE from the active RS CVn type star Lambda And during the phase of rotation period corresponding to maximum area coverage of the visible hemisphere by starspots and active regions. Enhancements during the flare in the ultraviolet emission line…
The temperature of C II emission-line formation regions in cool stars.
Carpenter, K. G.; Brown, A.
An investigation has been conducted of the temperature of C II emission-line formation regions in the outer atmospheres of late-type giant and supergiant stars. A distinct dichotomy is seen in the C II lambda 2325/lambda 1335 ratio between coronal and noncoronal stars. It is found that C II emission from noncoronal giant and supergiant stars comes…
IR Geminorum : indications of a massive white dwarf and a heated secondary in this new SU Ursae Majoris cataclysmic variable.
Szkody, P.; Shafter, A. W.; Cowley, A. P.
We report the discovery of a new SU UMa type cataclysmic variable through confirmation of a 102 minute superhump period during a supermaximum. The superhump has a 30% color-independent amplitude with a decrease in the equivalent widths of the Balmer absorption lines. Spectroscopic and photometric studies during quiescence show a 98-101 minute orbi…