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Multifrequency study of the very slow nova V723 Cas
Chochol, D.; Vittone, A. A.; Pribulla, T.
Multifrequency behaviour of the very slow nova V723 Cas is reviewed. The long-term photometry of the object revealed the orbital period 0.693265 days of the binary, quasi-periodic oscillations in the envelope of the burst white dwarf and 182 days periodicity of activity due to the mass transfer bursts from the red to the white dwarf probably cause…
A survey of 3He enhancements at 2-20 MeV/nucleon: Ulysses COSPIN/LET observations
Sanderson, T. R.; Marsden, R. G.; Tranquille, C. +1 more
We present the results of a survey of enhancements in the ratio of 3He/4 He as measured by the COSPIN/LET instrument on board the Ulysses spacecraft in the energy range 2-20 MeV/n. In the context of this study, all ratios of 3He/4 He above 0.05 are considered to be enhanced compared with the solar system value of ~0.0004. Previous studies have sho…
Role of low-frequency modes in organizing the inner heliosphere
Kunow, H.; Heber, B.; Lanzerotti, Louis J. +2 more
Cosmic ray proton data (125 to >2000 MeV) measured in the inner three-dimensional (3-D) heliosphere over the years from 1993 into 2000 by the KET instrument on the Ulysses spacecraft are examined. The data are parameterized and characterized by fitting products of spherical harmonic and sinusoidal frequency functions to three individual proton …
Optical and UV Spectral Diagnostics for GPS and CSS Sources
Dopita, Michael A.
In this paper I examine the use of optical and UV spectral diagnostic ratios to distinguish between gas which is locally shock-excited by the interaction with a jet and that which is photoionised by the central engine. In many cases key UV lines remain unobserved except in the case of high redshift radio galaxies. However, in one case, the nearby …
Fuzzy set theory applied to CME importance classification
Han, Zheng-Zhong; Tang, Yu-Hua
In this paper, fuzzy set theory is applied to a quantitative way of assigning importance class to coronal mass ejection (CME) events based on four observed characteristics, i.e. velocity, span, mass and kinetic energy. The weights to be associated with each of the characteristics and the membership functions of belonging to one of the three import…
Cosmic Ray Drifts at Solar Maximum
Ferreira, S. E. S.; Potgieter, M. S.; Heber, B.
A fully time-dep endent cosmic ray modulation model, based on the numerical solution of Parker's transport equation, is used to study the amount of particle drifts needed to explain the observed 2.5 GV electron to proton ratio (e/p) by the KET instrument on the Ulysses spacecraft. It is shown that the model successfully simulates the modulation of…
Reduction of ringing effects by an improved deconvolution algorithm. Application to A370 CFHT image of gravitational arcs
Mellier, Y.; Aime, C.; Roche, M. +2 more
We develop a self-consistent automatic procedure to restore information from astronomical observations. It relies on both a new deconvolution algorithm called LBCA (Lower Bound Constraint Algorithm) and the use of the Wiener filter. In order to explore its scientific potential for strong and weak gravitational lensing, we process a CFHT image of t…
Measuring the Fundamental Parameters of Hot Hydrogen-Rich White Dwarfs
Barstow, M. A.
This review considers the observations of hot, hydrogen-rich white dwarf stars, with particular reference to measurements of temperature, surface gravity and composition. Spectroscopic data from a variety of wavelength ranges are required for this work and, in particular, the important contributions from optical, ultraviolet and extreme ultraviole…
Infrared Astronomy with the Hubble Space Telescope and the Next Generation Space Telescope
Robberto, M.
I review the characteristics of NICMOS before and after the installation of the new cooling system. Recent results on high-redshift supernovae and star formation in the Large Magellanic Cloud are used to illustrate the NICMOS performance. I present the IR channel of WFC3, a fourth generation instrument to be installed on the Hubble Space Telescope…
Dynamics of quadruple system Finsen 332 = ADS 11640 = Hip 92027 = WDS
Olevic, D.; Cvetkovic, Z.
In 1829 Struve discovered a double star denoted as STF 2375 AB later on. Its separation was 2.2". It was noticed by Finsen from the Southern Observatory (Johannesburg) in 1953 that the components A and B are close binaries with separations about 0.15. The motion within this quadruple system - FIN 332 Aa and FIN 332 Bb - has been monitored from tha…