Search Publications
Mg II absolute line profiles for late-type stars and for spatially-resolved solar regions.
Pallavicini, R.; Cerruti-Sola, M.; Cheng, C. -C.
The authors present the results of a comparison of Mg II h and k line profiles and fluxes for late-type stars observed with IUE and for spatially resolved solar regions observed at comparable resolution by the NRL Spectrograph on Skylab. They show that the spatially resolved solar observations are in good agreement with the disk integrated stellar…
High-precision VLBI astrometry of the radio-emitting star sigma rho a step in linking the HIPPARCOS and extragalactic reference frames.
Preston, Robert A.; Lestrade, Jean-Francois; Phillips, Robert B. +1 more
VLBI observations of the optically bright radio-emitting star Sigma Coronae Borealis (Sigma CrB) have yielded its position relative to an angularly nearby quasar, its annual proper motion and its trigonometric parallax with formal uncertainties slightly better than 0.2 milliarcsec. This is the first result of the VLBI astrometric program we are co…
Photometric calibration of the International Ultraviolet Explorer (IUE) at low resolution: the LWP camera.
Gonzalez-Riestra, R.; Lloyd, C.; Cassatella, A. +2 more
The authors present and discuss the low resolution absolute calibration for the LWP camera of the International Ultraviolet Explorer (IUE). The calibration, implemented in routine processing of LWP low resolution images on December 22, 1987 at both GSFC and VILSPA IUE ground stations, is based on the last set of Intensity Transfer Function (ITF2) …
Global block adjustment simulations using the CPC 2 data structure
Zacharias, N.
Over 276,000 star positions on 5695 plates covering the entire southern hemisphere with a four-fold overlap pattern are used in rigorous block adjustment (BA) simulations to estimate the positional accuracy in terms of random and zonal systematic errors. A significant improvement of such global BA solutions are found as compared to BA solutions of…
IUE observations of UB-bright stars in M 3.
Cacciari, C.; Buonanno, R.; Corsi, C. E. +2 more
IUE UV observations of three "UV-bright" stars in M3 are presented. The brightest object - vZ1128 - is confirmed to be a bright Post-AGB star with logL/Lsun=3.09 and Te=30,000 K, which contributes about 25% of the integrated UV light from the cluster at λ=1500Å. The nature of the two other stars, i.e. 524 (logL/Lsun
The Structure of the Inner Arcsecond of R Aquarii Observed with the Hubble Space Telescope
Burgarella, Denis; Paresce, Francesco
The inner arcsec of R Aquarii has been observed with the Faint Object Camera on the Hubble Space Telescope. A simple and reliable linear deconvolution method is used to resolve the two features, designated C1 and C2 from radio observations, into several condensations. C1 is composed of four objects, designated C1a, C1b located at 0.099 arcsec from…
A photometric survey of the eclipsing RS CVn-type system RZ Eridani : starspot variability, circumstellar matter, tidal evolution.
North, P.; Burki, G.; Kviz, Z.
Results are presented of monitoring of the RS CVn-type eclipsing binary RZ Eridani, observed in the seven colors of the Geneva photometric system between November 1977 and April 1989. It is shown that the primary is an A8-F0IV star, which was stable during the 12 years of the survey. The secondary component, a G8-K0IV-III star, exhibits three kind…
Solar energetic and shock-accelerated particles observed between 1 and 4 AU by the Kiel Electron Telescope (KET) on board Ulysses
Sierks, H.; Kunow, H.; Wibberenz, G. +6 more
We present observations of solar energetic particles and shock-accelerated particles observed by the Kiel Electron Telescope (KET) on board the Ulysses spacecraft in the time interval 26 October 1990 to mid November 1991. Prompt events with diffusive propagation were observed mainly at small radial distances while at larger distances shock-related…
The X-ray variability of the Seyfert galaxy NGC 6814.
Fiore, F.; Massaro, E.; Barone, P.
We present the results of an accurate temporal analysis of five EXOSAT observations of the Seyfert 1 galaxy NGC 6814 covering about 2 yr. As firstly reported by Mittaz & Branduardi-Raymont (1989), the power spectrum of the longest (~1 d) observation is characterized by two major components: a low frequency noise which can be described, in the …
Observations of Plasma Dynamics in the Coma of P/Halley by the Giotto Ion Mass Spectrometer
Schwenn, R.; Balsiger, H.; Ip, W. -H. +7 more
Observations in the coma of P/Halley by the Giotto ion mass spectrometer (IMS) are reported. The high-energy range spectrometer (HERS) of the IMS obtained measurements of protons and alpha particles from the far upstream region to the near ionopause region and of ions of mass 12-32 at distances of about 250,000 to 40,000 km from the nucleus. Plasm…