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Coordinated multifrequency observations of the BL Lacertae objects MRK 180 and MRK 501.
Kondo, Y.; Mushotzky, R. F.; Urry, C. M. +8 more
The continuous spectra of the nearby BL Lac objects Mrk 180 and Mrk 501 have been investigated by making coordinated observations at X-ray, ultraviolet, optical, and radio wavelengths. The observations were planned in order to obtain single-epoch snapshots, or time-frozen spectra, of the emission at many different wavelengths. The spectra were fit…
The ionization structure of planetary nebulae. IV. NGC 6853
Barker, T.
Upgraded UV and IR data were taken of the planetary nebula NGC 6853 in the same region as previous optical data to improve the data base on various ionized species in the nebula. The spectral range 1400-9600 A was scanned, and good agreement was obtained between UV and optical ionization abundance data, although the 4267 A C II line yielded a C(2+…
IUE observations of Centaurus X-4 during the 1979 May outburst.
Raymond, J. C.; Dupree, A. K.; Holm, A. V. +3 more
Ultraviolet spectrophotometry of the X-ray transient/burst source Centaurus X-4 at several intervals during the peak and decay of the May 1979 X-ray transient event was obtained. The spectrum was characterized by a blue continuum with alpha = 0.0 + or - 0.3 (F/nu/ varies as nu to the alpha power) and strong emission lines of N V lambda 1240, C IV …
A study of the Herbig Ae-type stars UX ORI and CD -44 3318 based on IUE spectra, and on visual and infrared photometry.
The, P. S.; Tjin A Djie, H. R. E.; Remijn, L.
The spectral classifications of the two Herbig Ae stars UX Ori and CD-44 deg 3318 are reconsidered. The far-UV spectra of the stars are both similar to those of early A-type supergiants; however, the spectral types A2 III and A0-1 III are here derived for the respective stars based on continuum shapes, absorption features, and distance arguments. …
Ultraviolet, optical and infrared observations of the Wolf-Rayet contact-eclipsing binary CQ Cephei.
Bromage, G. E.; Howarth, I. D.; Willis, A. J. +5 more
IUE spectra of CQ Cep covering virtually all binary phases are analyzed, together with new UBVJKL photometry and remeasurements of radial velocities from archived optical spectra. The high resolution UV interstellar line spectrum strongly supports CQ Cep's membership in the Cep OB1 association. Continuum light curves in 15 wavebands, from 0.13 to …
Inflow of halo gas from the direction of the galactic North Pole.
Savage, B. D.; de Boer, K. S.
A far-UV echelle spectrum has been obtained of the UV-bright star vZ1128 in the globular cluster M3. This cluster lies in a direction 11° off the galactic North Pole at a distance of about 10 kpc. Only the usually strong interstellar lines are recognizable in the faint spectrum, and they show absorption at velocities from near +40 km s-1
IUE spectroscopy of the degenerate components in the Hyades close binaries V471 Tauri and HZ 9.
Sion, E. M.; Guinan, E. F.
Effective temperatures and gravities have been determined for the degenerate components in the Hyades close binaries V471 Tauri and HZ9 from model atmosphere analysis of IUE ultraviolet spectra. For V471 Tauri, T(e) = 35,000 K and log g is about 8. For HZ9, T(e) = 20,000 K and log g = 8. Both systems contain DA2 white dwarfs. No photospheric metal…
Observations of interstellar hydrogen and deuterium toward Alpha Centauri A.
Moos, H. W.; Linsky, J. L.; Landsman, W. B. +1 more
The authors present a composite profile of the Lyα emission line of α Cen A, obtained from 10 individual spectra with the high-resolution spectrograph aboard the satellite. There is excellent overall agreement with two previous Copernicus observations. Interstellar deuterium is detected, and a lower limit is set on the deuterium to hydrogen ratio …
The ultraviolet (IUE) spectra of the lambda Bootis stars.
Heck, A.; Jaschek, M.; Jaschek, C. +4 more
Ultraviolet spectra of several λ Boo stars and λ Boo candidates have been obtained with the IUE satellite in low- and in high-resolution. It is possible to discriminate the λ Boo stars from the normal A stars on low resolution spectra by their strong absorption features at λλ1600, 1657(C I), 1931(C I), and 3040 Å. The λ1600 feature, about 80 Å wid…
Variable blue supergiants in the Large Magellanic cloud : R 84, R 85 and R 99.
Stahl, O.; Leitherer, C.; Zickgraf, F. -J. +3 more
During a search for luminous blue variables in the LMC the three emission-line stars R 84 (OIafpe), R 85 (B5Iae), and R 99 (OBf:pe) have been found to show significant brightness and colour variations. Photometric and spectroscopic data from the UV to the IR have been used to discuss the nature of these variables. It is argued that they are closel…