Search Publications
Radial velocities and iron abundances of field RR Lyraes. II.
Garrido, R.; Solano, E.; Barnes, T. G. +1 more
This is the second of the papers devoted to derive radial velocities and iron abundances of field RR Lyraes observed by HIPPARCOS. Our abundances show good agreement with those in the literature obtained both from photometric (Delta S index) and spectroscopic methods. Binary candidates and stars misclassified as RR Lyraes in the original HIPPARCOS…
A photometric and spectroscopic study of the association LH47 in the superbubble N44 in the LMC
Bomans, D. J.; Dieball, A.; Will, J. -M.
The OB association LH47 inside the superbubble N44 in the Large Magellanic Cloud (LMC) is analyzed with CCD photometry. For the bright blue stars spectra in the optical and UV have been taken. The observed U, B, and V magnitudes and colours are converted to Teff and L. From isochrone fits to the colour magnitude diagram (CMD), we find a…
Mass determination of astrometric binaries with Hipparcos. I. Theory and simulation
Mignard, F.; Martin, C.; Froeschle, M.
The analysis of the observations of double stars made by the ESA satellite Hipparcos has involved a very specific processing to derive the relevant astrometric parameters. This required to distinguish between several categories of double stars according to the separation and orbital motion. We show that for close pairs with orbital period less tha…
Ultraviolet variability of the Seyfert 1 galaxy Fairall 9
Clavel, J.; Rodriguez-Pascual, P. M.; Wamsteker, W. +5 more
The large amplitude of the variations of the Seyfert I Galaxy Fairall-9 between 1978 and 1991 make this Active Galaxy especially suitable for a combined study in terms of reverberation analysis and photoionization modeling over the velocity field of the broad lines of its ultraviolet spectrum. We have combined our ultraviolet data with those avail…
Absolute proper motions for the calibration of the HIPPARCOS proper motion system
Klemola, A. R.; Geffert, M.; Schmoll, J. +1 more
Absolute proper motions of 48 Hipparcos stars in nine fields distributed over the northern hemisphere are presented. The proper motions have been recently used as part of the Bonn program for the extragalactic link of the Hipparcos proper motion system. We describe methods which have led to the absolute proper motions of the major part of the Bonn…
The changes in the UV emission lines of RR Telescopii from 1978 to 1993. I. The IUE SWP region
Hack, M.; Selvelli, P.; Zuccolo, R.
Line emission intensities and FWHMs in the range 1175-1900 Angstroms have been measured on high resolution IUE spectra of RR Tel taken from 1978 to 1993. The variations observed in the emission line intensities show a rather strong correlation with the line ionization. The decrease is of a factor larger than three and up to ten for the low-ionizat…
Wind variability in central stars of planetary nebulae. II.
Patriarchi, P.; Perinotto, M.
New high resolution IUE spectra of central stars of the planetary nebulae (CSPN) NGC 40, NGC 6543, NGC 6826, and BD +30 3639 have been obtained between August 1994 and September 1995 to explore the variability of their P Cygni profiles. The data have been analyzed together with previous observations of the same stars. Significant changes in the pr…
The FUOR characteristics of the PMS star BN Orionis inferred from new spectroscopic and photometric observations
de Winter, D.; van den Ancker, M. E.; Tjin A Djie, H. R. E. +3 more
BN Ori is a young emission-line star with a peculiar light curve. During the first half of this century the star showed strong irregular brightness- variations, similar to those of Herbig Ae stars. In the current half of the century the light curve resembles that of a FU Ori-object (FUOR, after Ambartsumian 1971). It can be characterised by an ini…
GPM1 - a catalog of absolute proper motions of stars with respect to galaxies
Rybka, S. P.; Yatsenko, A. I.
The description of the first version of the General Compiled Catalogue of Absolute Proper Motions (GPM1) for a sample of HIPPARCOS stars, derived with respect to galaxies within the plan called Catalogue of Faint Stars (KSZ, Deutch 1952), is presented. The principal aim of the GPM1 construction was to provide absolute proper motions of stars to de…
Absolute stellar proper motions with reference to galaxies of the M81 group
Meusinger, H.; Brosche, P.; Odenkirchen, M. +2 more
We report on the measurement of absolute proper motions of stars of magnitude 7 to 14.5 in a 2 deg X 2 deg field in the region of the M81 group of galaxies. This work is part of the Bonn program for the extragalactic link of Hipparcos. The proper motions were determined from a collection of photographic plates covering the time interval from 1894 …