Search Publications
Intrinsic parameters of galactic luminous OB stars.
Butler, K.; Kudritzki, R. P.; Herrero, A. +3 more
We present the results of a spectroscopic analysis of 25 galactic luminous OB stars. The gravities are in general lower than previously assumed, especially for giants. The helium abundances are also higher than normal in many cases. Using data from the spectroscopic analysis, radii, luminosities and masses are derived. The observed wind terminal v…
16. A tridimensional model of the galactic interstellar extinction.
Arenou, F.; Gomez, A.; Grenon, M.
The distribution of interstellar extinction has been mapped over the whole sky, using all available spectral and photometric data. The color excess distribution is modelled as a function of galactic latitude, longitude and distance within about 1 kpc from the sun. The model was used to predict the reddened Tycho and Johnson (B-V) colors, with the …
Reconstruction of the accretion disk in six cataclysmic variable stars.
Rutten, R. G. M.; van Paradijs, J.; Tinbergen, J.
The maximum-entropy eclipse-mapping algorithm is used to reconstruct images of the accretion disks of the novalike variable stars RW Tri, UX UMa, SW Sex, LX Ser, V 1315 Aql, and V363 Aur. The 2D disk intensity maps deduced from the light curves reveal the size of the disk and its radial intensity dependence. Black-body temperature maps deduced fro…
Near-infrared spectroscopy of galactic Wolf-Rayet stars.
Schmutz, Werner; Howarth, Ian D.
We present high-quality near-IR spectra of 24 Galactic WR stars, of a broad range of subtypes, selected as having known distances. The data cover the region 0.97-1.12 micron and include the 10830-A He I triplet. Measurements of He I and He II lines, together with the absolute magnitudes, yield temperatures, luminosities, mass-loss rates, and termi…
Orbital elements of S stars : revisiting the evolutionary status of S stars.
Jorissen, A.; Mayor, M.
The hypothesis of an evolutionary link between barium stars and the non-Mira S stars is discussed. The hypothesis of an evolutionary link between the barium stars and the non-Mira S stars is confirmed. The mass function distribution of S stars, indicating that the companions are likely white dwarfs, as is the case for barium stars, supports this h…
The SN 1986G in Centaurus A.
Schmutz, W.; Danziger, J.; Heydari-Malayeri, M. +10 more
We present photometric and spectroscopic observations of SN 1986 G, spanning up to one year after the explosion. The overall photometric behavior of this SN Ia results rather normal. The maximum at B = 1245+/-0.05 was reached on May 11,1986, then the decline to the inflection point was relatively fast (β_B_ = 12.0 mag/100 d), but similar to other …
A spectacular mass-loss event of the central star of Longmore 4.
Rauch, T.; Werner, K.; Heber, U. +3 more
We report on a dramatic change in spectral type of the central star of the planetary nebula Longmore 4. Its 'low state' spectrum is that of a PG 1159 star, i.e., of an extremely hot hydrogen-deficient (pre-) white dwarf, whereas its 'high state' spectrum has to be classified as of early Wolf-Rayet type (WC2-3). The observed spectral change reveals…
The TYCHO Input Catalogue. Cross- matching the Guide Star Catalog with the HIPPARCOS INCA Data Base.
Turon, C.; Didelon, P.; Egret, D. +2 more
A Tycho Input Catalogue of three million stars brighter than V = 12,1 has been produced for the needs of the Tycho data analysis. This catalog results from the cross-matching of a subset of the Hubble Space Telescope Guide Star Catalog with the Hipparcos INCA Data Base. The cross-matching procedure is explained and statistics about the magnitude d…
The extreme helium star BD -9 4395.
Heber, U.; Jeffery, C. S.
Simultaneous optical and UV spectroscopy is used to investigate both the photospheric variations and emission-line behavior of the extreme helium star BD-9 deg 4395. The photospheric parameters of the star are rederived from the optical spectra by the method of fine analysis, on the basis of up-to-date atomic data and new line-blanketed model atmo…
Variability pattern from X-ray to IR wavelengths in the active nucleus ofNGC 1566.
Alloin, D.; Pelat, D.; Baribaud, T. +1 more
This study presents the results of a multiwavelength monitoring of the active galactic nucleus in NGC 1566. Data collected in the X-rays, ultraviolet, visible and near-infrared domains have been combined together, in order to disentangle the various components and to better understand the patterns of variability in this active nucleus. At all wave…