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Abrupt changes in the C IV resonance lines of theta CR B.
Stalio, R.; Doazan, V.; Thomas, R. N. +2 more
It is noted that the Theta CrB far-UV spectrum changes from conspicuous presence, to complete disappearance, to reappearance at a higher velocity than the previous one, have occurred with a phase lag of about 3 years after the disappearance of a weak shell phase of short duration which was observed in the visible in 1979. This sequence is interpre…
The absorption near 1400 A in the spectra of additional DA white dwarfs.
Wegner, G.
Ultraviolet spectroscopic observations of five white dwarfs having published spectral types of DA made with the International Ultraviolet Explorer (IUE) satellite are reported. The three coolest objects: GD279 (0148 + 46), W485A (1327 - 08), and G231 - 40 (2117 + 53) have easily detected absorptions near lambda 1400. Of the two remaining stars, PG…
IUE observations of weak G-band stars.
Sneden, C.; Parthasarathy, M.; Bohm-Vitense, E.
High- and low-resolution ultraviolet spectra of several weak G-band giants have been obtained with the IUE satellite, to derive Be abundances and to search for degenerate companions. The abundances of Be in these stars are about log epsilon (Be) approximately -0.5. These values are in good agreement with the Be abundances of Hyades giants, and are…
On interstellar absorption toward Cepheus OB2.
Hobbs, L. M.
A weak interstellar absorption line which can be identified as the forbidden line of Fe X 6375 A is observed in the spectrum of the A2 Ia star Nu Cep, which is a member of the Cepheus OB2 association. The equivalent width, width, and radial velocity of the line differ indistinguishably from those of similar absorption previously detected uniquely …
Ultraviolet spectroscopy of hot young stars with infrared excesses : NGC 2264 - W 46, W 90 and W 100.
Sitko, M. L.; Simon, T.; Meade, M. R.
New ultraviolet data are combined with optical data to investigate the wavelength-dependent extinction of the stars W46, W90, and W100 in the young galactic cluster NGC 2264. The observations of W90 confirm the existence of anomalous (circumstellar) dust extinction with a ratio of total to selective extinction, R greater than 7. This extinction is…
Erratum - Detailed Observations of NGC4151 with IUE - Part Three - Variability of the Strong Emission Lines from 1978FEB to 1980MAY
Tanzi, E. G.; Tarenghi, M.; Perola, G. C. +8 more
Visual and ultraviolet spectrum of the eclipsing binary V367 Cygni.
Hack, M.; Engin, S.; Yilmaz, N.
V 367 Cyg is a single spectrum eclipsing binary (P = 18.6 d) classified as Beta Lyrae type. Spectroscopic observations during two successive cycles confirm previous studies and indicate that the shell spectrum does not vary greatly and does not present appreciable expansional velocity. The radial velocity of the shell lines may be explained by a r…
Exosat observation of the candidate X-ray counterpart of Geminga
Caraveo, P. A.; Bignami, G. F.; Mereghetti, S. +2 more
During a search for X-ray counterparts of the COS B>=100 MeV γ-ray sources (see refs 1, 2), observations using the Einstein Observatory revealed a new X-ray source, 1E0630 + 178, inside the ~1/2 square degree error box of the γ-ray source 2GC195+4, `Geminga'3. On the basis of its interesting properties, this source has been proposed …
The distribution of interstellar matter toward Tycho's supernova remnant and its relation to distance estimates.
Raymond, J. C.; Black, J. H.
Observations of interstellar absorption lines in the spectra of five stars in the direction of Tycho's Supernova Remnant are presented. The profiles show significant absorption at large negative velocities, - 50 to - 60 km/s (LSR). This information, together with the distances of the background stars, permits limiting distances to be assigned to t…
IUE observations of two extremes among contact binaries : AW Ursae Majoris and SW Lacertae.
Pringle, J. E.; Vilhu, O.; Rucinski, S. M. +1 more
The authors present IUE observations of AW UMa and SW Lac. These stars are the most extreme representatives of the A- and W-types of W UMa stars and might therefore be expected to differ most in their properties. The authors find that the stars are similar in their transition region emission (N V, C IV, Si IV) but differ markedly in their chromosp…