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Extended wings of the UV SI IV, C IV resonance doublets and the complex [Fe II] profiles in P Cygni.
Israelian, G.
We investigate the formation and the nature of the extended wings of the UV resonance lines of Si IV 1394, 1402A and C IV 1548 and 1550A in the spectrum of the LBV P Cyg. The effects of line blending in the neighbourhood of these lines were estimated by means of a grid of theoretical synthetic spectra, computed for the P Cyg model atmosphere. It i…
Imaging of Asteroid 4179 Toutatis with the Hubble Space Telescope
Weaver, H. A.; Noll, Keith S.; Storrs, A. D. +1 more
We obtained four images of the asteroid 4179 Toutatis during its close approach to the Earth on 10 December 1992 with the planetary camera of the Hubble Space Telescope. The distance between the Earth and Toutatis at the time of our observations was 0.0291 AU (4.35 × 10 6 km); a single planetary camera pixel width subtends a distance of…
Hubble Space Telescope Images of the Nuclear Star-forming Region in the Interacting Galaxy NGC 5930
Bower, Gary A.; Wilson, Andrew S.
High-resolution images of the spiral galaxy NGC 5930 have been obtained with the Planetary Camera aboard the Hubble Space Telescope in the emission lines of [O III] λλ4959, 5007 + Hβ and Hα + [N II] λλ6548, 6583, and their adjacent continua. NGC 5930 is the interacting companion of the Type 2 Seyfert galaxy NGC 5929. Five bright continuum knots, w…
Meridian circle reductions using preliminary HIPPARCOS positions.
Lindegren, L.; Mignard, F.; van Leeuwen, F. +7 more
New reductions of differential observations made by the Bordeaux and La Palma automatic meridian circles have been undertaken, replacing the positions of the FK5 reference stars by those in the Hipparcos 18-month intermediate solution. A remarkable improvement in the post-fit residuals of the classical least-squares adjustment is obtained for both…
The Gravitational Lens System Q0957+561 in the Ultraviolet
Michalitsianos, A. G.; Dolan, J. F.; Boyd, P. T. +8 more
Photometric and polarimetric observations of both images of the gravitationally lensed quasar Q0957 + 561 (z_em_ = 1.41) were obtained in the UV in 1993 with the High Speed Photometer on board the Hubble Space Telescope. The images exhibited no significant polarization in a bandpass centered on 2770 A (observer's frame); p <= 3.2% (2 σ upper li…
The TYCHO star mapper background analysis.
van Leeuwen, F.; Wicenec, A.
The Hipparcos star mapper detector background signal has been analyzed in the Tycho reductions for contributions due to the diffuse galactic light. The methods are presented by which the contributions from the two fields of view of the telescope are separated after elimination of background variations due to the radiation environment (Van Allen be…
Problems concerning the radio emission from Jupiter observed by ULYSSES after encounter.
Lecacheux, A.; Barrow, C. H.
Radio observations of Jupiter, made by the hi-band receiver of the Ulysses Unified Radio and Plasma (URAP) experiment before encounter, are generally consistent with observations of Jupiter made by the Voyager Planetary Radio Astronomy (PRA) experiment. After encounter, however, presumably due to the effects of beaming towards the extreme southerl…
Phase-resolved IUE and Optical Observations of the Polar BY Camelopardalis
Raymond, J. C.; Zucker, D. B.; Mason, P. +4 more
Time-resolved lUE observations of the asynchronous polar BY Cam (H0538 +608) over a period of 11 days show that the N V 1240 Å emission-line velocity varies on the orbital period, with an amplitude of 368±27 km s-1. The N V flux also varies on the orbital period, with maximum flux corresponding to maximum blue-shift. This behavior is se…
Fourier Parameters of Heliospheric Current Sheet and Their Significance
Schulz, Michael
If the path of the neutral line on the coronal source surface is expressible as a singlevalued function (colatitude θ vs longitude φ), then Fourier analysis of ctn θ with respect to φ leads to a simple algorithm for realistically mapping the neutral line outward to model the heliospheric current sheet (HCS) at distancesr≳1 AU. To be compatible wit…
The IUE Spectrum of the Planetary Nebula NGC 6751
Feibelman, Walter A.
We present the first high-dispersion lUE short-wavelength (SWP) spectrum of NGC 6751 (029.2 -05.9) from which log Nc = 3.9±0.05 cm-3, terminal wind velocity v∞ = 2450±150 km s-1, and a maximum mass-loss rate of Mṡ(max) 7.9 × 10-8 Msun yr-1 are determined. Emiss…