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The discovery of high-velocity flares in NV and the detection of carbon in the double degenerate binary GP COM
Horne, Keith; Marsh, T. R.; Wood, Janet H. +1 more
We present time-resolved ultraviolet spectra of the ultrashort-period binary GP Com taken with the Hubble Space Telescope. During our observations GP Com displayed spectacular variability in the dominant NV emission line which showed three large flares in 13h of observations. We isolate the flare spectrum which reveals CIV emission at a level of 0…
A search for wind variability in central stars of planetary nebulae.
Patriarchi, P.; Perinotto, M.
All the high resolution spectra of central stars of Planetary Nebulae (CSPN) obtained so far with the SWP camera of the IUE satellite have been examined for variability in their P Cygni profiles. The available data allowed to explore the constancy or changes of the line profiles in fourteen CSPN over time scales of months to various years. In nine…
Mirroring of fast solar flare electrons on a downstream corotating interaction region
Chaizy, P.; Pick, M.; Anderson, K. A. +5 more
We discuss an example of confinement of fast solar electrons by a discrete solar wind-interplanetary magnetic field structure on February 22, 1991. The structure is about 190,000 km in width and is clearly defined by changes in the direction of the magnetic field at the Ulysses spacecraft. This structure carries electrons moving toward the Sun as …
Satellites on Lyman Alpha Due to H-H and H-H + Collisions
Kielkopf, John F.; Allard, Nicole F.
We have experimentally observed satellites on Lyman- alpha arising from radiative collisions of excited atomic hydrogen with unexcited neutral hydrogen atoms or protons. The wavelength, relative intensity, and shape of features in the Lyman- alpha wing emitted by a laser-produced plasma in pure hydrogen agree with new theoretical calculations base…
EXOSAT Observations of the Low-Luminosity X-Ray Burster 4U 0614+091: Evidence for a Hard Power-Law Tail
Barret, Didier; Grindlay, Jonathan E.
We have analyzed archival EXOSAT observations of 4U 0614+091 as recorded by the Medium Energy experiment (2-10 keV). The data set consists of five spectra, all associated with low X-ray luminosities (L(X,1-20 keV) ≤ 2 × 1036 ergs s-1, d = 2 kpc). The spectrum corresponding to the highest intensity state (FX
Differences between the 0.35-1.0 MeV/nucleon H/He ratio in solar and Co-rotating events at high heliolatitude
Simnett, G. M.; Roelof, E. C.; Sayle, K. A.
We discuss measurements from the Ulysses spacecraft of the 0.35-1.0 MeV/nucleon H/He intensity ratio at high heliolatitudes. In early 1994 two transient solar events were detected in the gaps between particle intensity increases associated with the passage at low latitude of a co-rotating interaction region. The H/He ratio was ≳ one order-of-magni…
The Discovery of a Jetlike Feature from the Massive Star Herschel 36
Henning, T.; Stecklum, B.; Eckart, A. +2 more
The O7 V star Hershcel 36 has been studied in the near-infrared by ground-based high-resolution techniques. These observations and image restoration of Hubble Space Telescope (HST) planetary camera hydrogen alpha and (S II) images led to the detection of a jetlike feature. The interpretation of that feature as a jet is discussed in relation to a c…
Dark Auroral Oval on Saturn Discovered in Hubble Space Telescope Ultraviolet Images
Ben Jaffel, Lotfi; Sandel, Bill R.; Leers, Veronique
Hubble Space Telescope ultraviolet images of Saturn obtained with the Faint Object Camera near 220 nanometers reveal a dark oval encircling the north magnetic pole of the planet. The opacity has an equivalent width of ~11^circ in latitude and is centered around ~79^circN. The oval shape of the dark structure and its coincidence with the aurora det…
C IV and O VI Transitions in the Region lambda lambda 1100--2000 and Examples Found in IUE Spectra of Hot Stars
Feibelman, Walter A.; Johansson, Sveneric
We present Ritz wavelengths for more than 130 transitions of C IV and O VI in the range λλ1100-2000 and show examples of absorption features as seen in representative examples of high-dispersion IUE spectra of very hot (∼100,000 K) nuclei of planetary nebulae, white dwarfs, and PG 1159-type stars. The regions near He II λ640 and interstellar Si II…
The Elemental Composition in Energetic Particle Events at High Heliospheric Latitudes
Krupp, N.; Fränz, M.; Keppler, E. +2 more
The relative abundances of low energy ions (0.6 2.0 MeV/n) in solar energetic particle (SEP) and corotating interaction region (CIR) events have been measured by the EPAC experiment aboard Ulysses since launch in October 1990 until the present time. We give an overview of the abundances of heavy ions (He, C, Ne, Fe) relative to oxygen during energ…