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Tentative confirmation of an aurora on Uranus
Owen, T.; Caldwell, J.; Encrenaz, Th. +2 more
There have been three recent reports of the detection of Lyman-alpha radiation (due to atomic hydrogen, H, at wavelength 1,216 A) from Uranus by means of the International Ultraviolet Explorer (IUE) satellite. The interpretations of these results differ. Two reports conclude that there is a strong aurora on Uranus, but the third concludes that the…
UV radiation from the young Sun and oxygen and ozone levels in the prebiological palaeoatmosphere
Imhoff, C. L.; Canuto, V. M.; Levine, J. S. +1 more
UV measurements of young T-Tauri stars, resembling the Sun at an age of a few million years, have recently been made with the International Ultraviolet Explorer. They indicate that young stars emit up to 104 times more UV than the present Sun. The implications for the origin and evolution of O2 and O3 in the prebio…
High-energy γ-ray light curve of PSR0531 + 21
Caraveo, P. A.; Bignami, G. F.; Hermsen, W. +8 more
The Crab pulsar (PSR0531 + 21) was one of the earliest identified sources of high-energy γ radiation1-6. As such it was selected as the first object of detailed study by ESA's γ-ray astronomy satellite COS B, launched in August 1975. The experiment and mission have been described elsewhere7. In the first 6 yr of operation COS…
Bismuth abundance anomaly in a Hg-Mn star
Jacobs, J. M.; Dworetsky, M. M.
Strong absorption lines due to Bi II have been found in the Hg-Mn star HR7775 (HD193452) in high-resolution spectra obtained with the IUE. HR7775 was first recognized as a chemically peculiar star by Preston in 1972. Detailed examination of the optical spectrum at high resolution1 showed that it is one of the most extreme stars of the `…
Intense Lyα emission from Uranus
Durrance, S. T.; Moos, H. W.
The existence of intense atomic hydrogen Lyα emission from Uranus is demonstrated here by utilizing the monochromatic imaging capabilities of the International Ultraviolet Explorer (IUE) spectrograph. Our observations show increased emission in the vicinity of Uranus superimposed on the geocoronal/interplanetary background. If resonant scattering …
UV observations of TT Arietis and the magnetic rotator hypothesis
Jameson, R. F.; King, A. R.; Sherrington, M. R. +1 more
TT Arietis, one of the brightest cataclysmic variables, mv~10.2-->11.0, is usually classed as a novalike variable, but after a recent dip in brightness to mv~14.5, Krautter et al.1 suggested it to be a dwarf nova in an extended high state. Photometric light curves2-4 generally show a sinusoidal light …
Ly-alpha absorption at a high velocity in NGC1275
Boksenberg, A.; Snijders, M. A. J.; Briggs, S. A.
The results of a study of three spectra of the peculiar galaxy NGC1275 obtained with the SWP camera aboard the IUE satellite are reported and discussed. The absorption feature identified with Ly-alpha at 8200 km/s was clearly seen in all three spectra. The origin of this feature is attributed to the intervening galaxy responsible for the high velo…
IUE observations of variability and differences in the UV spectra of double quasar 0957+561 a, b.
Wilson, R.; Gondhalekar, P. M.
The continuum flux from 2500-2800 A and the emission flux in the Lyman alpha line were observed to change substantially in component A of the double quasar but not in component B. The equivalent width of the line increased by 50 percent in A but not in B, which was probably not due to instrument effects. It was expected that these changes should r…
Evidence for sulphur implantation in Europa's UV absorption band
Matson, D. L.; Nelson, R. M.; Lane, A. L.
The International Ultraviolet Explorer (IUE) spacecraft has obtained observations of the galilean satellites over the past 2 years which fortuitously span the periods of the Voyager encounters with the jovian system. Our IUE observing programme is designed to determine the UV spectral characteristics of the galilean satellites as a function of orb…
The nearby interstellar medium
Frisch, P. C.
The high dispersion spectrometer on board the International Ultraviolet Explorer (IUE) satellite was used to observe interstellar absorption lines in Rasalhague (α Oph). This star is located 18 pc from the Sun in the direction of the North Polar Spur, a prominent radio continuum feature in the Ophiuchus region of the sky. The satellite results, co…