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A massive helium star with a sufficiently strong magnetic field to form a magnetar
Wade, Gregg A.; Toonen, Silvia; Sana, Hugues +13 more
Magnetars are highly magnetized neutron stars, the formation mechanism of which is unknown. Hot helium-rich stars with spectra dominated by emission lines are known as Wolf-Rayet stars. We observed the binary system HD 45166 using spectropolarimetry and reanalyzed its orbit using archival data. We found that the system contains a Wolf-Rayet star w…
Time-Resolved Observations of Jupiter's Far-Ultraviolet Aurora
Casertano, Stefano; Ballester, Gilda E.; Krist, John E. +19 more
Simultaneous imaging and spectroscopic observations of Jupiter's far-ultraviolet aurora covering half a jovian rotation were made on 31 May 1994. The Hubble Space Telescope Wide Field Planetary Camera 2 images revealed dramatic and rapidly changing auroral features, including discrete longitudinal structures along the auroral ovals, with variable …
Halley's Confounding Fireworks
Kerr, Richard A.
The intensive worldwide campaign of observations of Halley's Comet repeatedly yielded data, particularly imagery, of sudden outbursts from the Comet. IUE data for Dec. 24, 1985 showed a brightness increase in the central coma by a factor of 2-3 over a 1-2 day period, followed shortly thereafter by spectra indicating a surge of ionized CO2 150,000 …
Remote Sensing of the Magnetic Moment of Uranus: Predictions for Voyager
Hill, T. W.; Dessler, A. J.
Power is supplied to a planet's magnetosphere from the kinetic energy of planetary spin and the energy flux of the impinging solar wind. A fraction of this power is available to drive numerous observable phenomena, such as polar auroras and planetary radio emissions. In this report our present understanding of these power transfer mechanisms is ap…
Ultraviolet Spectroscopy and the Composition of Cometary Ice
Feldman, P. D.
Our current knowledge of the composition of the cometary nucleus is largely inferred from observations of the gas and dust comae that are produced by sublimation of cometary ice when a comet is near the sun. During the past decade, far-ultraviolet spectroscopy from above the terrestrial atmosphere has shed new light on the physics and chemistry of…
Central Object of the 30 Doradus Nebula, a Supermassive Star
Savage, B. D.; Cassinelli, J. P.; Mathis, J. S.
R136 (HD 38268) is the central object of the 30 Doradus Nebula, a giant region of ionized hydrogen in the Large Magellanic Cloud. Observations of R136 at low and high spectral resolution with the International Ultraviolet Explorer reveal a peculiar hot object with a massive stellar wind. An outflow speed of 3500 kilometers per second and a tempera…
Io: Longitudinal Distribution of Sulfur Dioxide Frost
Matson, D. L.; Nelson, R. M.; Lane, A. L. +3 more
Twenty spectra of Io (0.26 to 0.33 micrometer), acquired with the International Ultraviolet Explorer spacecraft, have been studied. There is a strong ultraviolet absorption shortward of 0.33 micrometer that is consistent with earlier ground-based spectrophotometry; its strength is strongly dependent on Io's rotational phase angle at the time of ob…
Ultraviolet Night Airglow of Venus
Barth, C. A.; Stewart, A. I.
The night airglow spectrum of Venus in the ultraviolet is dominated by the v' = 0 progressions of the gamma and delta bands of nitric oxide. The bands are produced by two-body radiative recombination of nitrogen and oxygen atoms. Since the source of these atoms is in the dayside thermosphere, the night airglow is a tracer of the day-to-night therm…
International Ultraviolet Explorer probes the universe.
Hartline, B. K.
The impact of the International Ultraviolet Explorer (IUE), launched in January 1978, on ultraviolet astronomy is reviewed. An assortment of firsts has been achieved, including the first UV observation of a supernova, the first high-resolution UV spectrum of a star in another galaxy, and the first evidence that acetylene is present in the upper at…
International Ultraviolet Explorer Probes the Universe
Karplus Hartline, Beverly