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HST-GHRS observations of Sirius A. III. Detection of a stellar wind from Sirius A
Ferlet, R.; Vidal-Madjar, A.; Lallement, R. +2 more
Observations of Sirius A with the GHRS instrument on board the Hubble Space Telescope revealed the presence of absorption features in the blue wings of the strong MgII and Hi resonance lines in the velocity range from -20km/s to -80km/s. These features are probably due to the stellar wind of Sirius rather than to blends of photospheric lines becau…
The stellar wind of an O8.5I(f) star in M31. A determination of mass loss rate and metallicity.
Lennon, D. J.; Bianchi, L.; Pauldrach, A. W. A. +4 more
We rediscuss the UV spectrum of OB78#231, an O8.5I(f) star in the Andromeda galaxy M31, which has been obtained with the Faint Object Spectrograph on the Hubble Space Telescope by Hutchings et al.. The spectrum has been reextracted with better knowledge of background, calibration, and scattered light. The empirical analysis of the stellar wind lin…
A study of emission lines variability of the active galaxy PKS 0521-365.
Pian, E.; Falomo, R.; Scarpa, R.
Optical spectrophotometry of the active galaxy PKS 0521-365 over a period of 7 years is reported, together with the analysis of IUE archival spectra. The Hα emission line intensity varied by more than a factor of 2 during the monitoring. Similar amplitude variations are observed in the optical and UV continuum, which however are not simply correla…
Hot HB stars in globular clusters: physical parameters and consequences for theory. II. NGC 6397 and its short blue horizontal branch.
de Boer, K. S.; Heber, U.; Schmidt, J. H. K.
New visual spectra of 14 blue horizontal-branch (BHB) stars in NGC 6397 and 2 spectra from the literature are used to derive atmospheric parameters (T_eff_, logg) for these stars. With the theoretical surface brightness for the derived stellar parameters and with the given distance of the cluster one then can calculate the radius, the luminosity, …
Astrometry of double stars with HIPPARCOS
Badiali, M.; Cardini, D.; Emanuele, A. +13 more
After the processing of 30 months of the observations carried out by HIPPARCOS it is possible to provide reliable statistics on the number of double and multiple stars to be detected at the mission completion and on the quality of the astrometric and photometric results on these objects. About 21000 stars have been recognized as non-single, includ…
Diffuse interstellar bands and UV extinction curves. The missing link.
Desert, F. -X.; Jenniskens, P.; Dennefeld, M.
The connection between diffuse interstellar bands and components of the interstellar ultraviolet extinction curve, decomposed according to the Fitzpatrick & Massa scheme, is analysed from new observations of several DIBs in the line of sight to 28 stars measured by IUE. We find that the strength of the 217.5nm bump positively correlates with D…
Hot subluminous stars at high galactic latitudes. V. UV spectra of binary and peculiar hot subdwarf stars.
de Boer, K. S.; Heber, U.; Moehler, S. +2 more
UV spectra observed with the IUE satellite of hot subdwarfs showing peculiarities in optical spectra are presented. Most peculiarities can be explained by the presence of a cool companion star. Assuming that the UV region is not affected by a cool companion, the fluxes of the hot component of the binary stars are modelled in the UV using theoretic…
Discovery of three UV-bright z>2 quasars.
Reimers, D.; Hagen, H. -J.; Rodriguez-Pascual, P. +1 more
We report the discovery within the Hamburg quasar surveys and subsequent UV observations with IUE of 10 bright, high-redshift quasars. While 3 objects appear completely absorbed below 3200A, HS 1103+6416 (z=2.19), HS 1307+4716 (z=2.13), HE 1122-1649 (z=2.40), HE 1230-2347 (z=1.85), and HE 1211-1322 (z=1.12) have been detected with the IUE short wa…
Search for gravitational wave trains with the spacecraft ULYSSES.
Vecchio, A.; Comoretto, G.; Giampieri, G. +8 more
We report on the search for periodic gravitational wave in the mHz band conducted with the spacecraft ULYSSES. Gravitational wave signals generally provide information about the distance of the source; ULYSSES' data have a "ken" for each kind of source one looks for; for binaries the galactic centre is accessible to our experiment. The Neyman Pear…
A photometric and spectroscopic study of BG Canis Minoris.
Mukai, K.; de Martino, D.; Bonnet-Bidaud, J. M. +5 more
The photometric and spectroscopic analysis presented here has revealed new observational features in the Intermediate Polar BG CMi. We have found a strong variability of the dominant light pulsations, rotational (913s) and orbital (3.23hr), on a timescale of years. Variations in the amplitude of the spin pulsation with epoch generally appear to be…