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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…
Scattering of interplanetary radio waves at kilometric wavelengths
MacDowall, Robert J.; Hess, Roger A.
We report on measurements of the angular size of Jovian radio sources measured by the URAP instrument on the Ulysses spacecraft. The angular size is found to be substantially larger than that expected from the geometric size of the source, which is essentially a point source when viewed from Ulysses. This increase in size is due to scattering of t…
Reduction of the binary stars Δm measurements, obtained with the speckle interferometer of BTA of SAO RAS, into the standard photometric system
Zhuchkov, R. Ya.
For magnitude difference, measured with the speckle interferometer of the 6m telescope of SAO RAS, corrections for transformation from interferometer's photometric system into standard Johnson-Cousins V R I bands are calculated. The reduction accuracy is 0.01m - 0.02m. To determine the correction one has to know the magnitude…
The Structure of Proper-Motion Diagrams for Nearby Stars
Vereshchagin, S. V.; Reva, V. G.; Chupina, N. V.
The structure of the proper-motion diagrams for an ensemble of nearby field stars is analyzed using a simple model. For comparison, the observed proper-motion diagram is constructed using data of the Hipparcos catalog. A complete description is given of the modification of the van Altena method, which allows stars with similar space motions to be …
A comparative estimation of the accuracy of modern astrometric catalogues
Nefedjev, Yu. A.; Rizvanov, N. G.; Shaimukhametov, R. R.
A method for a comparative estimation of the accuracy of astrometric catalogues in the random meaning is offered. The estimation is done by comparison of star coordinates in the catalogues under study with star coordinates in the HIPPARCOS catalogues for various epochs. Variances of star positions and proper motions in the catalogues under investi…
A survey searching for the epoch of assembling of Hubble types
Pasquali, Anna; de Mello, DuÍlia F.
We have started a survey of galaxies at intermediate redshifts using the HST-STIS parallel fields. Our main goal is to analyse the morphology of faint galaxies in order to estimate the epoch of formation of the Hubble classification sequence. The high resolution of STIS images (0.05″) is ideal for this work and enables us to perform a morphologica…
ESA INTEGRAL and Cataclysmic Variables
Hudec, R.; Hroch, F.; Strobl, J. +1 more
Analysis of a coronal loop on the limb
Martens, P. C. H.; Cirtain, J. W.; Winter, H. D.
The ability to accurately measure the temperature and density of the solar atmosphere is essential to understanding the physical nature of Coronal loops. After data has been corrected to account for cosmic ray incidents on the CCD and instrumental effects, there are additional sources of error that must also be addressed. We applied a correction t…