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Imaging of Four Planetary Nebulae in the Magellanic Clouds Using the Hubble Space Telescope Faint Object Camera
Boksenberg, A.; Barbieri, C.; Weigelt, G. +18 more
Using the Faint Object Camera on-board the Hubble Space Telescope, we have obtained images of four planetary nebulae (PNe) in the Magellanic Clouds, namely N2 and N5 in the SMC and N66 and N201 in the LMC. Each nebula was imaged through two narrow-band filters isolating [O III] λ5007 and Hβ, for a nominal exposure time of 1000 s in each filter. Si…
The Ionizing Radiation Field of NGC 4388 and Its Relation to the Extranuclear Emission-Line Regions
Colina, Luis
New long-slit spectroscopic observations of NGC 4388 and the extranuclear emission line regions around it are used to investigate the characteristics of the ionizing source and the structure of the extended emission-line regions. The measured luminosity of the [Fe VII) λ6087 emission line detected in the nucleus of NGC 4388 is interpreted as evide…
From Fairall 9 to High-z Objects: Pattern of Change in Ionization Structure
Zheng, Wei; Binette, Luc; Fang, Li-Zhi
A study of 79 IUE spectra of the Seyfert galaxy Fairall 9 shows a considerable change in the continuum shape which can be characterized by several sections. The flux at 3075 A changes in approximate proportion to the optical and X-ray flux, suggesting that they may be a part of the power law. The apparent fourfold change in the continuum slope bet…
Hubble Space Telescope FOS Observations of KPD 0005+5106: A Subluminous WN-WC Descendant with Ongoing Mass Outflow?
Sion, Edward M.; Downes, Ronald A.
The results are reported of spectroscopic observations of the ultrahigh excitation, helium-rich, prewhite-dwarf KPD 0005 + 5106 obtained with the HST Faint Object Spectrograph (FOS) in 1991 May and July with the red (FOS/RD) and blue (FOS/BL) Digicon detectors. The data reveal a rich line spectrum both in absorption and in emission with ultra-high…
The Spectra of IC 418 and IC 5117 from 1.5 to 1.75 Microns
Kwok, Sun; Zhang, C. Y.
Near-infrared spectra of planetary nebulae IC 418 and IC 5117 in the wavelength range 1.5-1.75 microns are reported. More than 10 members of the Brackett line series are detected superposed on a strong continuum. Analysis of the spectra shows that the observed flux ratios of the Brackett lines are in good agreement with the recombination line theo…
The Unusual Ultraviolet Chromospheric Spectrum of the R Coronae Borealis Star, V854 Centauri (NSV 6708), at Minimum Light
Judge, P. G.; Stanford, S. A.; Clayton, Geoffrey C. +2 more
Results are presented of IUE observations of a decline of the recently discovered R CrB star, V854 Cen. These observations are of particular interest because they include spectra taken at 7 mag below maximum light. The 'chromospheric' emission spectra show striking differences from UV spectra of other R CrB stars in decline. Strong emission appear…
The Ultraviolet Color Gradient in the Late-Type Spiral Galaxy M33
O'Connell, Robert W.; Bohlin, Ralph C.; Landsman, Wayne B. +3 more
The ultraviolet surface brightness and color distributions for the late-type spiral galaxy M33 are derived from images at 1520 and 2490 A that were obtained by the Ultraviolet Imaging telescope (UIT) on the Astro Spacelab mission. although the surface brightness shows a general decline with radius, the dominant spiral arms cause significant deviat…
The Luminosity of the Double-Mode Cepheid Y Carinae
Evans, Nancy R.
IUE spectra of the double-mode Cepheid Y Carinae have been used to determine the spectral type of the binary companion. From the companion spectral type (B9.O V), the absolute magnitude of the Cepheid is found to be -2.94 mag, with an estimated uncertainty of +/-0.3. This luminosity is in good agreement with that from the period-luminosity-color r…
A Spectroscopic Search for Colliding Stellar Winds in O-Type Close Binary Systems. II. Plaskett's Star (HD 47129)
Wiggs, Michael S.; Gies, Douglas R.
New evidence for colliding winds in the massive O-type binary system Plaskett's star is reported. High S/N ratio spectra of the H-alpha and He I 6678 emission lines are presented, and their orbital phase-related variations are examined in order to derive the locations and motions of the high-density gas in the system. Radial velocity cures for sev…
EXOSAT Observations of the Be/X-Ray Binary 4U 2206+54
Saraswat, Priyamvada; Apparao, Krishna M. V.
We present the X-ray observations of the Be star binary system 4U 2206 + 54 made with the EXOSAT satellite during the period 1983-1985. The observations were carried out on three occasions, each separated by roughly a year. The source was active during the 1983 and 1985 observations and several short duration flares were observed. The spectrum, du…