Search Publications
The Ongoing Outburst of the Eclipsing Symbiotic Nova AS 296: The First 1200 days
Munari, Ulisse; Whitelock, Patricia A.; Gilmore, Alan C. +3 more
Ultraviolet, optical, and infrared photometry is reported for the symbiotic star AS 296, spanning the first 1200 d of its outburst which began in June 1988. The effects of the outburst were restricted to the wavelength interval 2200-7500 A. The progress of the event was followed through two maxima and two eclipses of the hot source by the M5 III c…
Multiwavelength observations of RV Tauri stars. I. AC Herculis.
Evans, A.; Shenton, M.; Albinson, J. S. +6 more
We present ultraviolet, optical and infrared (including IRAS) observations of the RV Tauri star AC Her. IRAS LRS spectra suggest that the dust shell of AC Her may consist of both silicon carbide and silicates, and modeling of the optical-IR flux distribution suggests the presence of at least two distinct dust shells, the larger of which may be the…
Hubble Space Telescope Spectroscopy of OB Stars in M31
Bianchi, L.; Hutchings, J. B.; Lamers, H. J. G. L. M. +2 more
We have obtained UV spectra of two luminous hot stars in M31 with the Hubble Space Telescope. The stars are of late O and WN spectral type and lie on opposite sides of M31. We derive UV extinction curves for M31 which differ from both the Galaxy and the LMC. We find differences between the 15 absorbers in both lines of sight in M31 and in the Gala…
Outbursts by Low-Mass White Dwarfs in Symbiotic Variables
Sion, Edward M.; Ready, Christian J.
We have investigated the nature of P Cygni-like features in the high resolution IUE spectra of the symbiotic variables BF Cyg and EG And by looking for orbital phase-dependent variations in the structure and velocity of the C IV (1550 A) resonance doublet in 10 archival IUE high-dispersion spectra of these systems and by comparing their profiles w…
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 origin of the X-ray emission in 3C 273 and 3C 120.
Walter, R.; Courvoisier, T. J. -L.
We present an analysis of simultaneous X-ray and ultraviolet observations of the two quasars 3C 273 and 3C 120 which exhibit very similar multi-waveband spectra. This investigation is limited to the long term variations observed in the two spectral bands and to their correlations. In both objects, the X-ray and ultraviolet lightcurves are not coup…
Ulysses observations of escaping VLF emissions from Jupiter
MacDowall, R. J.; Kaiser, M. L.; Desch, M. D. +5 more
The Ulysses URAP experiment has detected Jovian radio emissions in the VLF range at distances from Jupiter in excess of 1.5 A.U. The URAP observations represent the first synoptic observations of Jupiter in the VLF band, 3 to 30 kHz. In this band lie the low-frequency extent of the bKOM emission, the escaping continuum emission, and the Jovian typ…
Ultraviolet and optical spectra of central stars of halo planetary nebulae.
Pena, M.; Torres-Peimbert, S.; Ruiz, M. T.
UV and optical spectrophotometric data on central stars of eight Population II planetary nebulae are analyzed. Visual magnitudes, spectral classification, color temperatures, and luminosities are derived from these data. All the stars in the sample exhibit an absorption-type spectrum, and most of them have normal H and He photospheric abundances, …
Quasi-linear velocity space diffusion of heavy cometary pickup ions on bispherical diffusion characteristics
Coates, A. J.; Johnstone, A. D.; Huddleston, D. E.
We consider an ion transport equation describing the source, convection, adiabatic acceleration, and quasi-linear velocity diffusion of cometary pickup ions. The equation is solved numerically along solar wind plasma flow lines for the environment of comet Halley, to obtain distributions at positions on the Giotto spacecraft trajectory which may b…
IR survey of OB emission-line stars in the SMC : detection of a new B E supergiant, AV 172.
Stahl, O.; Zickgraf, F. -J.; Wolf, B.
We surveyed bright SMC emission-line stars in the infrared (JHK) in order to search for more B[e] supergiants in this galaxy by means of their IR excesses. One new star, AV 172, with the B [e] type IR excess was detected. Optical and IUE spectroscopy of this star showed it to be a B8 [e]Ib supergiant. Our survey showed that in the SMC four B [e] s…