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A Study of the Young Massive Cluster N90 in the SMC
Thompson, I. B.; Hutchings, J. B.; Cartledge, S. +1 more
We present optical and UV spectra of O and B stars in the compact nebulous cluster Henize N90 in the SMC. The brightest stars are of type O and B, although our optical and UV classifications do not all agree closely. We discuss the spectra, effective temperatures, bolometric luminosities, extinction, stellar winds, and the evolutionary state of th…
UV Observations of the Cool DBQA5 White Dwarf LDS 678A: Limits on the Atmospheric Composition, Pressure Shift, and Gravitational Redshift Derived from C I 2479
Sion, Edward M.; Koester, Detlev; Liebert, James W. +5 more
A high-resolution ultraviolet spectrum of the helium-rich degenerate LDS 678A, obtained with the International Ultraviolet Explorer (IUE) satellite, is presented. LDS 678A is the coolest metallic line degenerate (DQ or DZ) yet observed with the IUE echelle. These observations provide a detailed line profile of the strong C I 2479 absorption line a…
On the Utility of Low Resolution IUE Spectroscopy of the 2800 A MG II Lines as a Stellar Chromosphere Indicator
Smith, Graeme H.; O'Connell, Robert W.; Burstein, David +2 more
Low resolution IUE spectroscopy of the 2800-A Mg II h and k lines is shown to provide a useful means for documenting chromospheric activity among relatively young dwarf stars. An index I(Mg II) has been defined which measures the integrated flux in the region 2784-2814 A relative to the flux interpolated from nearby comparison regions. Values of t…
Ultraviolet and Optical Spectra of High-Ionization Seyfert Galaxies with Narrow Lines
Peterson, Bradley M.; Korista, Kirk T.; Wagner, R. Mark +2 more
Ultraviolet and optical spectra are presented for three unusual Seyfert galaxies (Mrk 1239, Mrk 42, and Mrk 493) that resemble Seyfert 1 galaxies in that they have strong high-ionization lines and strong nonstellar continua, but resemble Seyfert 2 galaxies in that the widths of their permitted lines are as narrow as the widths of their forbidden l…
The Ultraviolet Variations of K Scuti
Monier, R.
This paper reports on low resolution observations of the pulsating star Delta Scuti (F2IIIp) obtained with the International Ultraviolet Explorer (IUE) at different phases of the 4 hr and 40 min pulsation cycle. The ultraviolet flux varies in phase with the optical flux measured with the Fine Error Sensor (FES). The amplitude of the ultraviolet va…
Ultraviolet Observations of a Bright Southern Quasar
Strauss, Michael A.; Kirhakos, Sofia; Fisher, Karl B. +2 more
We present low-resolution ultraviolet spectra of the QSO 09149 - 6206 (z = 0.057) obtained with the International Ultraviolet Explorer. The spectrum shows strong emission lines of Ly α, C IV, C III], Mg II, and Fe II. The Fe II blend centered at 2080 A is unusually strong; this may be a consequence of overcorrection for the 2175 A silicate feature…
Attogram Dust Cloud a Million Kilometers from Comet Halley
Kissel, Jochen; Utterback, Nyle G.
Particle-impact ion mass spectrometers carried on the Giotto and two Vega spacecraft missions to Comet Halley in 1986 produced unexpected signals almost one million kilometers from Halley which can be attributed to high number densities of dust particles with masses of order 10 to the -18 g. The data imply that up to several percent of the total m…
The Ultraviolet and Visible Light Variability of BP Tauri: Possible Clues for the Origin of T Tauri Star Activity
Simon, Theodore; Vrba, Frederick J.; Herbst, William
BP Tau is a moderate-strength T Tauri star, which has previously been studied photometrically by Vrba et al. (1986, 1989) and shown to have a 7.6-day light cycle. Here, BP Tau was reobserved in order to monitor this star with the IUE satellite. In conjunction with the UV spectroscopy, nearly simultaneous ground-based optical photometry was also ob…
The IRAS Low-Resolution Spectra of Planetary Nebulae
Volk, Kevin; Cohen, Martin
This paper presents the low-resolution spectra of 170 planetary nebulae observed by IRAS, most of which were not included in the Atlas of Low-Resolution Spectra. These have been classified into eight groups based upon the spectral morphology, with emphasis on the dust continuum rather than the spectral lines. The Low-Resolution Spectrometer (LRS) …
Observations of SK -69 203 and the Interstellar Extinction Toward SN 1987A
Walborn, Nolan R.; Fitzpatrick, Edward L.
We have obtained optical and UV spectroscopic observations of the Large Magellanic Cloud (LMC) star Sk - 69^deg^ 203, which is located in the 30 Doradus region of the LMC, approximately 2.2 arcmin north of the position of SN 1987A. The optical data reveal Sk - 69^deg^ 203 to be a B0.7 Ia supergiant with a moderate nitrogen enhancement. The UV spec…