Search Publications
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…
Observations and models of the UV/soft X-ray spectrum of the quasar PG 1116+215.
Molendi, S.; Ulrich, M. -H.
The radio quiet quasar PG 1116+215 has been observed four times with the ROSAT-PSPC, once during the All-Sky Survey and three times in pointed observations including one lasting 24320 seconds (25300 counts). Contemporaneous IUE observations were secured for two of the pointed observations. Overall the PSPC spectra at all 4 epochs can be reasonably…
Extragalactic symbiotic systems. II. Hubble Space Telescope observations of S 63 and Linsay 358.
Vogel, M.; Nussbaumer, H.
We present ultraviolet spectra of two symbiotic systems in the Magellanic Clouds obtained with the Faint Object Spectrograph onboard the refurbished Hubble Space Telescope. Because of the known distances to the LMC and SMC, and because of the high sensitivity of HST, accurate luminosities and radiation temperatures of the hot radiation source in S…
HIPPARCOS minor planets: first step towards the link between the HIPPARCOS and the dynamical reference frames.
Bec-Borsenberger, A.; Bange, J. -F.; Bougeard, M. -L.
The observations of minor planets are of particular interest for determining a possible rotation between the Hipparcos and the dynamical reference frames. In order to evaluate these unknowns, Hipparcos data are compared to the values calculated from the equations of motion. The satellite's observations are related to intermediate reference frames …
Particle events associated with local type III radio emission and Langmuir waves in the interplanetary medium.
Chaizy, P.; Pick, M.; Reiner, M. +3 more
The first detection of local type III radio emissions at the fundamental and harmonic of the plasma frequency was made by the Ulysses spacecraft when it was in the ecliptic plane and between ~1.4 and ~2.2AU from the Sun. In-situ Langmuir waves were observed simultaneously with each local radio event, indicating the presence of an electron beam at …
UV observations of the polar system RE 1938-461.
Mukai, K.; de Martino, D.; Mouchet, M. +1 more
We present IUE orbital phase resolved observations of the polar system RE 1938-461. We detect a strong variability of the prominent emission lines, C IV (1550 A), He II (1640 A) and N V (1240 A) at the orbital period of 140 min. Line velocity shifts are also detected with amplitudes and phasing consistent with those of the optical lines. We sugges…
Schmidt plate astrometric reductions using preliminary HIPPARCOS and TYCHO data
Makarov, V. V.; Evans, D. W.; Bastian, U. +9 more
New reductions of Schmidt plate measurements have been performed, using preliminary Hipparcos and Tycho data for the astrometric reference stars. The measurements reported here have been obtained with the MAMA automatic measuring machine of the Centre d'Analyse des Images in Paris. The Hipparcos data considered, the `combined 30-month solution', o…
Blue stragglers and horizontal branch stars in the core of the globular cluster M3.
Burgarella, D.; Paresce, F.; Quilichini, V.
The core of the Galactic globular cluster Messier 3 (NGC 5272) has been imaged through the f/96-F140W, f/96-F220W and f/96-F346M ultraviolet filters of the Faint Object Camera onboard the Hubble Space Telescope (HST) down to an ultraviolet magnitude of ~20. We measure a high specific frequency of blue stragglers stars (BSS), f_BSS_=0.29 in the obs…
Is this orbit really necessary? III. On the use of Hipparcus double-star measurements for orbit computation.
Dommanget, J.
In this paper the advisability of computing some double star orbits is discussed. As a conclusion, it appears that the Hipparcos double star measurements of relative positions will not essentially contribute to an improvement in our knowledge of double star orbits.