Search Publications
The nature of the sharp-lined A1V star HD 72660
Varenne, O.
In order to specify the nature of the sharp-lined A1V star HD 72660, its effective temperature and surface gravity have been determined using two different methods. First, the ultraviolet energy distribution of HD 72660 has been compared with that of the normal A0 star HD 10939 and with the predictions of two model atmospheres. Secondly, the param…
Numerical simulation of the dust flux on a spacecraft in orbit around an aspherical cometary nucleus - I
Fulle, M.; Rodionov, A. V.; Crifo, J. F.
This study is the first investigation of the dust collection by a spacecraft orbiting a cometary nucleus, which is based on a physically consistent ab-initio model of the dust distribution in the vicinity of an aspherical comet nucleus. The homogeneous bean-shaped nucleus of Crifo & Rodionov (1997a) is used, with updated parameter values adapt…
HR 1817: the EUV properties of an active F dwarf
Mullan, D. J.; Mathioudakis, M.
We examine the coronal properties of the active F dwarf HR 1817. Photometric observations with EUVE show that the source is in a near-continuous state of flare-like activity. Using IUE and EUVE spectroscopic observations we construct the emission measure distribution in the 10(4) -10(7.2) K temperature range. These observations reveal a hot corona…
OH lines in the FIR spectra of the OH megamaser galaxies IRAS 20100-4156 and 3Zw35
Quirrenbach, A.; Kegel, W. H.; Hertenstein, T.
Using the SWS and LWS instruments on board of the ISO spacecraft, we searched for OH-lines in the FIR spectra of the two OH megamaser galaxies IRAS 20100-4156 and 3 Zw 35. The lines at 34 mu and 53 mu were detected in absorption with certainty in the spectrum of IRAS 20100-4156 and probably in the spectrum of 3 Zw 35. From the measured equivalent …
Dust extinction and intrinsic SEDs of carbon-rich stars. III. The Miras, CS, and SC stars
Bergeat, J.; Knapik, A.; Rutily, B.
The present work is an extension of a recent study by Knapik & Bergeat (\cite{knapik97}), and Bergeat et al. (\cite{berge98b}) henceforth called Papers I and II, respectively. The spectral energy distributions (SEDs) of about 440 carbon-rich stars and the interstellar extinction observed on their line of sights were analysed. The methods origi…
Interstellar reddening from the HIPPARCOS and TYCHO catalogues. II. Nearby dust features at the NGP associated with approaching HI gas
Knude, J.; Høg, E.
The Hipparcos and Tycho Catalogues offer an interesting possibility to study the local distribution of the interstellar reddening from the combination of data contained in the catalogues: Hipparcos parallaxes, Tycho B - V and spectral and luminosity classification compiled from the literature, mainly the Michigan Catalogs. In some cases the distan…
Adaptive optics observations of luminous infrared galaxies. II. Imaging of the merging galaxy Arp 299
Rouan, D.; Doyon, R.; Rigaut, F. +2 more
We present adaptive optics observations of the Luminous Infrared Galaxy, Arp 299. This merging galaxy (NGC 3690) is the site of a very powerful starburst activity. Very high angular resolution observations at 2.2mic reveal many super-clusters of newly formed stars. Those clusters feature intrinsic luminosities and surface densities well above the …
An atmospheric model for the ion cyclotron line of Geminga
Caraveo, P. A.; Bignami, G. F.; Mignani, R. P. +3 more
Recent optical/UV data of Geminga (Mignani et al. 1998) have strengthen the significance of the emission feature present over the thermal continuum best fitting the EUV/soft X-ray data. Here we present a phenomenological model interpreting the data in terms of an ion cyclotron feature, arising from a thin outer layer of hot plasma covering Geminga…
Modelling the Sun as an active star. I. A diagnosis of photometric starspot models
van Driel-Gesztelyi, L.; Oláh, K.; Kővári, Zs. +1 more
We provide a diagnosis of photometric starspot models through modelling active areas on the Sun using softwares originally written for starspot modelling. The data we used were one-dimensional measurements of the Sun in radio (10.7 cm, DRAO, Canada) and in soft X-rays (GOES satellites). In these wavelengths the response to magnetic activity result…
X-type interactions of loops in the flare of 25 September 1997
Falewicz, R.; Rudawy, P.
The evolution and properties of the GOES C7.2 class solar flare observed in the NOAA 8088 active region on 25 September 1997 were studied with data taken by the Wroclaw Large Coronagraph/MSDP in Hα, Yohkoh/SXT and GOES X-rays as well as SOHO/MDI magnetic and SOHO/EIT ultraviolet observations. The observed properties of the flare are consistent wit…