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Software for the Analysis of Emission Line Nebulae
Shaw, Richard A.; Dufour, Reginald J.
A set of software tools has been developed for the IRAF/STSDAS environment to derive the physical conditions in a low-density (nebular) gas given appropriate diagnostic emission line ratios; and lien emissivities given appropriate emission line fluxes, the electron temperature (T_e) and density (N_e). The package is based on the five-level program…
Far-Ultraviolet and Optical Spectroscopy of the Detached White Dwarf-M Dwarf Binary RE J1629+780
Sion, Edward M.; Barstow, Martin A.; Holberg, Jay B. +1 more
We present optical and far ultraviolet observations, including IUE high and low dispersion spectroscopy of the (DA2+dM4-5) close binary, RE J1629+780, a very bright ROSAT EUV source. The optical data reveal emission reversals in the cores of the Balmer lines, which vary in strength but reveal no evidence of wavelength shifts reflecting orbital mot…
The IUE Absorption Spectrum of the Nucleus of NGC 246: Mostly C IV and O VI
Feibelman, Walter A.
We present a list of more than 140 absorption features and their equivalent widths for the central star of the planetary nebula NGC 246 as observed in the wavelength range lambda-1169-lambda 2000. High signal-to-noise ratios are achieved by coadding nine high-dispersion SWP spectra, representing a total of nearly 22 hrs observing time. The IUE spe…
IUE Spectroscopy of the Nova-Like Variable BZ Cam: Characteristics of its Peculiar Wind Outflow
Sion, Edward M.; Fabian, Dirk; Griffith, Daniel
We have analyzed 15 IUE low resolution SWP spectra of the peculiar hot nova-like object BZ Camelopardalis (= 0623+71), which is associated with a bow shock nebula. We determined approximate relative orbital phases of a series of spectra obtained continuously over a 28 hour time baseline by using the newly determined orbital period (P=0.1535 days) …
The Variable Velocity of Theta Carinae
Walborn, Nolan R.; Lloyd, C.; Stickland, D.
A study of the radial velocity variations of the bright, peculiar B star, theta Carinae, using published optical velocities and new IUE data, fails to confirm any of the orbital periods proposed for this system. Instead a new period of 2.203020 +- 0.000017 days is found and it is also suggested that there is a second period at about 25 days. Previ…
Variability of IUE Spectra of the Pulsating Nucleus of the Planetary Nebula K 1-16
Bond, Howard E.; Feibelman, Walter A.; Kaler, James B. +1 more
We report on some subtle changes which were detected in old IUE low dispersion spectra of the pulsating central star of the planetary nebula K 1-16. Although most of the data were taken more than ten years ago, the improved data reduction techniques and more accurate line identifications that have become available only recently permit measurement …
The Hot Stars in Symbiotic Systems
Muerset, Urs
Symbiotic stars are interacting binaries, consisting of a late giant and a very hot companion, whose radiation ionizes the wind from the cool star. They strike the observers by their complex spectra and variability. A small subgroup, the symbiotic novae, undergo outbursts with an amplitude of several magnitudes and a duration of several decades. T…