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Rotational modulation of hydrogen Lyman alpha flux from 44i Bootis.

Vilhu, O.; Neff, J. E.; Rahunen, T.

Observations with IUE that cover the entire 6.4 hr orbital cycle of the late-type contact binary 44i Bootis are presented. Intrinsic stellar hydrogen Lyman alpha emission flux was determined from low-resolution IUE spectra, compensating for geocoronal emission and for interstellar absorption. The variation of the stellar Lyman alpha emission flux …

Ultraviolet Observations of the Planetary Nebula NGC 2242

Garnett, Donald R.; Dinerstein, Harriet L.

We present IUE observations of the high-ionization planetary nebula NGC 2242. The ultraviolet spectrum exhibits stong emission lines of C IV, He II, C III], and [Ne IV], plus weaker emission from O IV and N IV. We have also obtained narrow-band imaging of NGC 2242 in the He II 4686 A emission line; comparison of the λ 4686 flux from this image wit…

The UV Spectrum of Pluto-Charon: IUE Observations from 2600 to 3100

Stern, S. A.; Skinner, T. E.; Trafton, L. M. +2 more

Observations of the UV spectra of the Pluto-Charon system were obtained between 1987 and 1988 using the large aperture of the IUE long-wavelength prime spectrograph. At the resolution and SNR of the data, no gas-phase spectral identifications were made. The present data indicate a geometric albedo of 0.35 + or - 0.05. Curve fitting the geometric a…

The X-Ray Variability of PKS:2155-304 - a Power Spectrum Analysis

Maraschi, L.; Tagliaferri, G.; Stella, L. +2 more

The bright BL Lac object PKS 2155-304 was observed with EXOSAT 9 times between 1983 and 1985 for a total of 80 hours. During some observations the source appeared stable, while during others, flare-like activity was observed, the intensity doubling in less than an hour. Here we present a power spectrum analysis of the 3 brightest observations. Sig…

IUE Observations of the Interstellar Medium toward beta Geminorum

Moos, H. W.; Murthy, J.; Linsky, J. L. +4 more

A dispersion IUE spectrum of the hydrogen Ly-alpha emission line of the nearby late-type star Beta Gem is presented. Values are determined for the density, velocity, dispersion, and bulk velocity of the interstellar H I toward the star, showing agreement with previous IUE results for stars in the same general direction (Murthy et al., 1987). It is…

Analysis of the Velocity Law in the Wind of the Be Star lambda Pavonis

Sahade, Jorge; Kondo, Yoji; Chen, Haiqi +1 more

This paper reanalyzes the IUE spectra of Lambda Pavonis secured in 1982 (Sahade et al.). It is found that the profiles of the broad UV lines are either rotationally broadened or nonrotationally broadened and that the rotationally broadened profiles can be sorted out in two groups characterized by rotational velocity values of 170 km/s and of 210 k…

The Temperatures of White Dwarfs in Accreting Binaries

Szkody, Paula; Sion, Edward M.

Long-term observations of the dwarf nova WZ Sge with an outburst recurrence time of 33 years are studied. The results indicate that the UV flux reached an equilibrium value at about the end of 1986; this means that the UV flux continued to decrease for 8 years after outburst. If the underlying dwarf has provided a dominant amount of the UV flux si…

Galactic Interstellar Abundance Surveys with IUE. III. Silicon, Manganese, Iron, Sulfur, and Zinc: Erratum

Shull, J. Michael; van Steenberg, Michael E.

Sanduleak's Star (LMC Anonymous): Its Similarity in the Far-Ultraviolet with the Luminous Object eta Carinae and SN 1987A

Kafatos, M.; Michalitsianos, A. G.; Shore, S. N.

Spectra obtained in the far UV wavelength range 1200-2000 A with the International Ultraviolet Explorer (IUE) of the peculiar emission object LMC Anonymous, or Sanduleak's Star in the Large Magellanic Cloud, indicate the presence of circumstellar-high-excitation gas, which is rich in CNO processed material. Although LMC Anonymous is a field star w…

The ultra-violet spectrum of the peculiar early-type supergiant, HD 157038.

Dufton, P. L.; Lennon, D. J.

Ultra-violet spectra of the nitrogen rich supergiant, HD 157038, are presented and compared with those of the normal supergiant, HD 148379. The P-Cygni profiles of the Si IV and C IV resonance lines are very similar, implying that the stars have similar masses; this is evidence against HD 157038 being in a post red supergiant evolutionary stage an…