Search Publications
The Optical Spectrum of the Planetary Nebula NGC 2440
Hyung, Siek; Aller, Lawrence H.
Wavelengths and identifications have been provided for approximately 300 lines between 3660 and 10125 Å in the spectrum of the bipolar planetary nebula NGC 2440. These lines measured with the Hamilton echelle spectrograph at Lick Observatory and supplemented by published IUE results are used to construct diagnostic diagrams and derive ionic concen…
A Long-Period Spectroscopic Binary in the O-Star Multiple System HD 193322
Bolton, C. T.; Fullerton, A. W.; Gies, D. R. +8 more
We present radial velocity measurements and a single-lined spectroscopic orbit for the bright O-type star, HD 193322A, which we show to be a 311 day binary system that has a distant third companion (detected by speckle interferometry) in a 31 yr orbit. We suggest that the speckle companion appears in the spectrum as a broad-lined component of earl…
Constraints on the Radial Velocity Curve of HDE 245770 = A0535+26
Wang, Z. X.; Gies, D. R.
We present new radial velocity measurements from IUE high-dispersion spectra of HDE 245770, the Be companion of the X-ray transient binary system, A0535+26. We formally derive the semiamplitude of the star's binary motion by fitting the UV and published radial velocity measurements with the other orbital parameters fixed according to the neutron s…
Recalibration of the Wilson-Bappu Effect Using the Singly Ionized Magnesium K Line
Mena-Werth, Jose; Scoville, Frederick
A new calibration of the Wilson-Bappu effect is presented using data from a survey of the singly ionized magnesium (Mg ii) h and k lines (near 280 nm) taken from the archives of the International Ultraviolet Explorer satellite. Our sample consisted of 94 stars with absolute magnitudes derived from parallaxes reported from Hipparcos. We describe th…
A Search for an Emission-Line Region in the Hydrogen-deficient Carbon Star HD 182040
Clayton, Geoffrey C.; Ayres, T. R.; Brunner, Andrew R.
A long-exposure short-wavelength IUE spectrum of the hydrogen-deficient carbon (HdC) star HD 182040 does not show any detectable emission in the C II lambda1335 line. It is not certain whether this absence of emission is intrinsic or due to the large uncertainties in the distance, absolute luminosity, and reddening toward HD 182040. If intrinsic, …
Is the Galactic Halo Planetary Nebula PN G243-37.1 an ``O VI Sequence'' Variable Object?
Feibelman, Walter A.
Archival IUE spectra of the Galactic halo planetary nebula PN G243-37.1 have been reprocessed by the NEWSIPS routine. The new results show a much richer emission-line spectrum than has previously been reported. Several C iii, C iv, O v, and possibly O vi features were detected. P Cygni line profiles could not be identified with certainty. The He i…
An IUE Spectroscopic Study of the Ultra-Short-Period Dwarf Nova T Leonis in Outburst
Sion, E. M.; Huang, M.; Fabian, D. +2 more
The IUE archive contains numerous low-resolution spectra of dwarf novae in outburst but relatively little synthetic spectral analyses of them using realistic accretion disk models with spectral lines. We have examined a series of previously unstudied archival IUE low-resolution short-wavelength prime spectra of the SU UMa-type ultra-short-period d…
Rotationally Broadened Synthetic Spectra for HST and IUE Observations of Exposed White Dwarfs in Cataclysmic Variables
Sion, E. M.; Nguyen, Quyen; Fabian, Dirk +2 more
In many dwarf novae during quiescence, the underlying white dwarf dominates the flux in the far ultraviolet. By observing these exposed degenerate stars with the Hubble Space Telescope Goddard High Resolution Spectrograph and Faint Object Spectrograph (HST GHRS and FOS), the white-dwarf rotation rates can be determined or constrained by fitting sy…