Search Publications
IUE Spectroscopy of U Cephei during the Mass Flow Outburst of 1986 June
Kondo, Yoji; McCluskey, George E., Jr.; Olson, Edward C.
The interacting Algol-type binary U Cep underwent another of its irregularly occurring transient high-mass flow events during June 1986. For the first time, high-resolution ultraviolet spectroscopy of U Cep during such an event was possible. High-resolution spectra in the far-ultraviolet and near-ultraviolet were obtained with IUE. These spectra s…
The Atmospheric Eclipse of 31 Cygni in the Ultraviolet
Eaton, Joel A.
Theoretical spectra have been compared with high-dispersion IUE observations for the 1982 atmospheric eclipse of 31 Cyg (B4 V + K4 Ib). Chromospheric column densities, excitation temperatures, turbulence, and ionization are determined. It is found that temperature increases with height in the chromosphere, showing a range 5000 - 14,400K for four l…
The Ionization Structure of Planetary Nebulae. VIII. NGC 6826
Barker, Timothy
Spectrophotometric observations of emission-line intensities over the spectral range 1400 to 1700 A were made in seven positions in the planetary nebulae NGC 6826. The O(++) electron temperature varies little from 8900 K throughout the nebula; the Balmer continuum electron temperature averages 1500 K higher. The wavelength 4267 C II line intensiti…
The Complex Wind of the Central Star of the Planetary Nebula Abell 78
Feibelman, Walter A.; Kaler, James B.; Henrichs, H. F.
The authors have observed with the high-dispersion camera of the IUE the broad P Cygni profiles of C IV, N V, and O V that arise from Abell 78's nucleus. They find a terminal velocity to the wind that is close to 3670±30 km s-1, a positive velocity gradient, and an approximate mass loss rate of ≡4×10-9M_sun;yr-1. S…
The Ultraviolet-Optical-Infrared Energy Distribution of LMC X-3: Observation of an Accretion Disk around a Black Hole
Maraschi, L.; Tanzi, E. G.; Chiappetti, L. +4 more
LMC X-3 was observed quasi-simultaneously at UV (IUE), optical, and IR (ESO, La Silla) frequencies in 1987 January. The overall energy distribution exhibits a broad peak around 10^15^ Hz. The UV flux appears well in excess of that measured by us in 1986 March, which can be attributed to the noncollapsed star in the system. The excess emission can …
Quasi-simultaneous Ultraviolet Optical and Infrared Observations of the BL Lacertae Object PKS 0048-09
Maraschi, L.; Tanzi, E. G.; Bouchet, P. +2 more
The first International Ultraviolet Explorer (IUE) observations of the BL Lacertae object PKS 0048-09 were obtained on 1987 January 7 and 8, when the object was in a moderately high optical state (m_v_ ~ 15.5 mag). Quasi-simultaneous optical-IR spectrophotometry allows deriving the detailed energy distribution from ~10^14^ to ~2.5 x 10^15^ Hz. Com…
Cooling Flow in the 2A 0335+096 Cluster of Galaxies
Singh, K. P.; Westergaard, N. J.; Schnopper, H. W.
We present the surface brightness distribution of hot intracluster gas in the 2A 0335+096 cluster of galaxies, obtained from X-ray imaging observations with the Einstein Observatory and the EXOSAT Observatory. The intracluster gas is found to be nonisothermal. The surface brightness is deprojected to obtain density and temperature profiles of the …
Ultraviolet Spectroscopy of R Coronae Borealis
Holm, A. V.; Doherty, L. R.
Observations of the hydrogen-deficient supergiant R CrB were obtained with the IUE over an interval of 54 days in order to study the nature of this star's irregular, small-amplitude variations in light. By chance, the series of observations coincided with a dip in the light intermediate between the normal fluctuations and the deep declines associa…
An Improved Photometric Analysis of SX Aurigae
Peters, Geraldine J.; Linnell, Albert P.; Polidan, Ronald S.
The photometric analysis reported leads to four principal conclusions: 1. The SX Aur system consists of two normal main-sequence stars. The components are very close to the inner Roche limiting surface. 2. The primary component is extremely close to contact with its inner Roche lobe, as well as can be judged from the photometric solution. It is in…
Detection of Extragalactic Absorption in the Ultraviolet Spectrum of the BL Lacertae Object PKS 2155-304
Maraschi, L.; Tanzi, E. G.; Treves, A. +2 more
The complete collection of ultraviolet spectra (1200-3000 A) of PKS 2155-304 taken with IUE in l979-1986 is reanalyzed with the aim of producing a high signal-to-noise ratio spectrum. As a result of co-adding the best exposed spectra a number of absorption lines are found, most of which can be identified with expected interstellar species in our G…