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Photospheric velocity gradients in B1 supergiants.
Massa, D.; Shore, S. N.; Wynne, D.
We present IUE spectra for a set of B1 supergiants. These data clearly demonstrate that the Si III 1300A multiplet (lower level 6.6 ev above ground) becomes progressively more asymmetric with increasing luminosity or, equivalently, mass loss. In the most luminous supergiants, the cores of the 1300A multiplets become displaced by up to -150 km/s re…
The Sun as a Star: High Spectral Resolution Solar Data Degraded to Low-Dispersion IUE Resolution
Doyle, J. G.; Cook, J. W.
High spectral resolution (about 0.06 A) solar data for an active region and a large two-ribbon flare degraded to the typical resolution of low-dispersion (about 5 A) spectra of the IUE satellite are presented. This clearly shows the amount of detail yet to be acquired in stellar spectra and indicates the main spectral regions where line blending i…
Faint Object Spectrograph Observations of the Large-Redshift Gravitational Lens Candidate 1208+1011
Maoz, Dan; Schneider, Donald P.; Jannuzi, Buell T. +2 more
We report HST spectroscopic observations of the z = 3.8 gravitational lens candidate 1208+1011. Low-dispersion (R = 200) Faint Object Spectrograph data, covering the wavelength range 3700-7800 A, were obtained for each of the two components (V ~18.3 and 19.8 mag) and for a comparison (blank) field; the fainter component and the blank field are bot…
X-Ray Observations of Planetary Nebulae with Binary Nuclei
Nousek, J. A.; Apparao, K. M. V.; Berthiaume, G. D.
Einstein and EXOSAT satellite observations of X-ray emission from the planetary nebulae A63 and LoTr 5 are reviewed. Both of these systems contain binary central stars. No flux was detected from A63 (central star UU Sge). LoTr 5 (central star IN Com) is a previously unreported X-ray emitter; it showed no statistically significant X-ray variability…
Double star CCD astrometry and photometry
Irwin, M. J.; Argue, A. N.; Bunclark, P. S. +3 more
Results are presented for angular separation, position angle and V and R photometry for 2373 binary stars, obtained with the CCD camera on the 1-m Jacobus Kapteyn Telescope at La Palma. The stars are part of the Input Catalogue of the Hipparcos Astrometric Satellite launched in 1989 August, and the purpose of our measurements is to assist in the s…
Energy structure of the accretion disc corona in X 1822-371.
Hellier, Coel; Mason, Keith O.; Williams, O. R.
Ginga observations of the LMXB X 1822-371 show that the broad orbital modulation and the eclipse are deeper at higher energies. This is explained if the X-ray emitting corona produces softer emission at greater heights from the disc plane, which suggests that either the corona is optically thick, or that the illuminating X-rays are anisotropic. Fu…
Highly Ionized Gas in the GUM Nebula and Elsewhere: A Comparison of IUE and Copernicus Satellite Results
Savage, Blair D.; Edgar, Richard J.
The data from six high-dispersion IUE echelle spectra are averaged in order to obtain an interstellar absorption line spectrum with an S/N of about 30 and a resolution of about 25 km/s. The interstellar lines of C IV and Si IV are very strong and broad and N V is detected. The profiles for these species and Al III are compared to the Copernicus sa…
The massive stars in the R136 region of 30 Doradus.
Elson, Rebecca A. W.; Schade, David J.; Thomson, Robert C. +1 more
We present U and B photometry, based on Hubble Space Telescope observations, for 26 stars in the R136 region of the young cluster 30 Doradus in the Large Magellanic Cloud. It has been suggested that rich star clusters form through the coalescence of clumps, and it seems likely that the R136 region is such a clump. If it is in virial equilibrium th…
Computation of ephemerides for long-period variable stars for the HIPPARCOS mission
Figueras, F.; Barthes, D.; Mennessier, M. O. +2 more
In order to predict the luminosities of LPVs observed by Hipparcos, many visual light curves, characterized by irregularly spaced data, were analyzed using original and complementary methods. The obtained power spectra, including amplitudes and phases, are utilized in the computation of the ephemerides. The predictions are regularly checked with o…
UV spectroscopy of Z Chamaeleontis. II - The 1988 January normal outburst
Sonneborn, G.; Charles, P. A.; Hassall, B. J. M. +3 more
IUE observations taken during the 1988 January normal outburst of Z Cha are presented and a detailed comparison with the 1987 April superoutburst is made. The most important difference from the superoutburst is that the normal outburst continuum flux shows less than 10 percent orbital variation away from the eclipse, implying that there is no 'coo…