Search Publications
Missions
Journals
Publication Years
IUE observations of the bright Herbig AE star HD 104237.
Talavera, A.; Catala, C.; The, P. S. +4 more
IUE observations are noted to indicate that HD 104237 exhibits the same UV, visible, and IR spectral properties as the Herbig Ae stars AB Aur and HR 5999. It is accordingly concluded that HD 104237 is a 2.1 solar-mass Herbig AE star. With respect to HR 5999, the chromospheric and transition region emission-line flux of HD 104237 is sufficiently la…
Scattering of X-rays on the winds of supergiant X-ray binaries.
Haberl, F.
Monte-Carlo simulations of Thomson scattering of X-rays in the stellar wind of OB stars in supergiant X-ray binaries show that at least part of the low-energy excess seen in the X-ray spectra during phases of high absorption can be explained by scattering of X-rays around a dense region in the wind obscuring the direct radiation. In the case of 4U…
Short term H-alpha variations in two Herbig PMS stars : HR 5999 and HD 52721.
Catala, C.; The, P. S.; Tjin A Djie, H. R. E. +2 more
We present high spectral resolution observations of Hα as well as V photometry and IUE observations for two Herbig pre-main sequence stars, HR 5999 and HD 52721. These observations, performed in 1985, were aimed at studying short-term variations of the Hα line, within one night and from night to night. Hα spectra of comparison stars are also displ…
IUE Spectra of the Eclipsing Binary NN Serpentis
Wood, Janet H.; Marsh, Thomas R.
Low-resolution SWP and LWP IUE spectra are used to fit the temperature and angular radius of the white dwarf in the detached eclipsing binary NN Ser. It is found that the redenning to the system has E(B-V) of 0.05 +/-0.05, the white dwarf temperature is 60,000 +/-10,000 K, and the age of the white dwarf is less than 10 exp 7. The shape of eclipse …
Energy Distributions of Symbiotic Novae
Kwok, Sun; Bryan, Greg L.
The IRAS low-resolution spectra of three recent symbiotic novae are fitted with a dust continuum radiative transfer model. It is found that the dust shells are detached from the photosphere and that the sizes of the inner radii are correlated with times since outburst. An analysis of the IUE spectra of HM Sge at different epochs suggests that the …
EXOSAT Observations of the X-Ray Source 2S 0114+65
Singh, K. P.; Apparao, Krishna M. V.; Bisht, P.
The Exosat satellite made X-ray observations of the Be star binary system 2S 0114 + 65 on five occasions during the period 1983-1986. Several X-ray flares of a few hours duration were observed. The hardness ratio shows an inverse correlation with intensity, indicating that the intensity variation is due to absorption. This implies density irregula…
Calculation of the new series of the Earth orientation parameters in the HIPPARCOS reference frame.
Vondrak, J.
The succesful lauchch of the HIPPARCOS astrometric satellite by the ESA in August 1989 enables the past observations, obtained by optical astrometry all over the world since the beginning of the century, to be re-reduced in order to get the Earth orientation parameters in a homogeneous and unique celestial reference frame. Completely new algorithm…
Iron Kα lines and the absorption structure of intermediate polars
King, A. R.; Watson, M. G.; Norton, A. J.
The X-ray spectra of Intermediate Polars typically show a large absorbing column density and a strong iron K emission line. Using observations made with EXOSAT and GINGA, we show that the lines probably have a fluorescent origin but that their equivalent widths are too large to be due to fluorescence solely in the material which gives rise to the …
Spectroscopic binary orbits from ultraviolet radial velocities. Paper 8: LZ Cephei (HD 209481)
Stickland, D. J.; Howarth, Ian D.; Koch, R. H. +2 more
We present a study of the double-lined spectroscopic binary LZ Cep based on high-resolution IUE spectra. We determine the radial velocities by using a cross-correlation technique incorporating profile fitting; this allows measurements of velocity separations down to unusually small values. The final velocity curve has a small but significant eccen…
Discovery of a new bright southern QSO.
Wisotzki, L.; Wamstecker, W.; Reimers, D. L.
WithIn the newly started Hamburg/ESO survey for bright southern quasars the low-redshift QSO HE 1029-1401 (z = 0.086) was found by automated search on objective prism plates and subsequently confirmed by slit spectroscopy. With v = 13.86 it is among the three brightest QSOs in the sky and the brightest ever found by optical selection. Broad band o…