Search Publications
IUE Observations of Rapidly Rotating Low-Mass Stars in Young Clusters: The Relation between Chromospheric Activity and Rotation
Simon, Theodore
If the rapid spindown of low-mass stars immediately following their arrival on the ZAMS results from magnetic braking by coronal winds, an equally sharp decline in their chromospheric emission may be expected. To search for evidence of this effect, the IUE spacecraft was used to observe the chromospheric Mg II emission lines of G-M dwarfs in the n…
Plasma parameters near the Comet Halley bow shock
Coates, A. J.; Wilken, B.; Kessel, R. L. +2 more
Plasma data from the Johnstone Plasma Analyzer on Giotto are used in a Rankine-Hugoniot analysis of Comet Halley bow shocks. The shock normals are obtained and compared with models and other estimates. Proton bulk parameters from the Fast Ion Sensor inbound are analyzed, and water group densities from the Implanted Ion Sensor (IIS) are obtained wh…
Observations of SK -69 203 and the Interstellar Extinction Toward SN 1987A
Walborn, Nolan R.; Fitzpatrick, Edward L.
We have obtained optical and UV spectroscopic observations of the Large Magellanic Cloud (LMC) star Sk - 69^deg^ 203, which is located in the 30 Doradus region of the LMC, approximately 2.2 arcmin north of the position of SN 1987A. The optical data reveal Sk - 69^deg^ 203 to be a B0.7 Ia supergiant with a moderate nitrogen enhancement. The UV spec…
Ultraviolet Fe VII Absorption Lines in Planetary Nebula Nuclei, Hot Subdwarfs, and Hot Degenerate Objects
Feibelman, Walter A.; Bruhweiler, Frederick C.
Results are reported from a search for Fe VII absorption lines in data from high-dispersion IUE-SWP observations of PN nuclei (PNN), hot subdwarfs (HSDs), and hot white dwarfs (HWDs). The data-reduction techniques employed are outlined, and the results are presented in extensive tables and sample spectra and characterized in detail. Absorption in …
Time dependence of the UV resonance lines in the cataclysmic variables SU UMa, RX And and 0623+71.
Verbunt, Frank; Drew, Janet E.; Woods, A. John
IUE observations of the dwarf novae SU UMa and RX And, and of the nova-like variable 0623 + 71 are presented. At the time of observation, SU UMa and RX And were in outburst. All three systems show variability in the wind-formed UV resonance lines of N V 1240 A, Si IV 1397 A and C IV 1549 A on timescales of hours. The amplitude of variation is smal…
An Astrometric Catalogue of Radio Stars
Walter, H. G.; Hering, R.; de Vegt, Ch.
The first part is presented of a radio star catalog encompassing 186 objects whose selection was guided by the priority criteria of the Hipparchos Input Catalogue Consortium. Since these criteria are well suited to the need for linkage of ground-based optical systems to radio reference frames, this first selection is also considered a suitable bas…
Spectrophotometry of the shell around AG Carinae.
Dufour, Reginald J.; Mitra, P. Mila
Spatially-resolved long-slit spectrophotometry are presented for two regions of the shell nebula around the P-Cygni variable star AG Carinae. The spectra cover the 3700-6800 A wavelength range. Emission-line diagnostics are used to derive extinction, electron temperatures, and densities for various positions in the nebula. The chemical abundances …
The UV spectrum as a signature of the lambda Bootis character.
Gerbaldi, M.; Faraggiana, R.; Boehm, C.
The spectra of all the stars previously classified as Lambda Bootis stars and observed by the IUE satellite at low resolution, in the short wavelength range, are analyzed. The usefulness of this spectral range for classifying the Lambda Boo stars is shown; the UV criteria used to distinguish the Lambda Boo stars from other metal-deficient stars ar…
The Orbit and Companions of the Classical Cepheid FF AQL
Evans, Nancy Remage; Teays, Terry J.; Welch, Douglas L. +1 more
New radial velocities of the classical Cepheid FF Aql have been obtained and combined with previous observations to provide a revised orbit. A companion has been detected at 1800 A in IUE spectra with a spectral type of A9 V to F3 V. If the Cepheid has an evolutionary mass, then the mass ratio is M1/M2 = 3.8. A companion recently detected by speck…
A New Method to Determine the Interstellar Reddening toward WN Stars
Conti, Peter S.; Morris, Patrick W.
The emission lines in Wolf-Rayet stars may be utilized to determine the absorption properties of their line-of-sight interstellar medium. One can measure the line strengths both in terms of the equivalent widths (in units of the continuum) and fluxes. In general, in a comparison of two lines, the equivalent width ratio is extinction independent; i…