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Ultraviolet observations of the peculiar supernova remnant in NGC 4449.
Gull, T. R.; Raymond, J. C.; Fesen, R. A. +1 more
IUE spectra were obtained of the emission region in the irregular galaxy NGC 4449 that has been identified as a young, oxygen-rich supernova remnant embedded in an H II region. The spectra show a blue continuum with a strong C IV 1550 P Cygni feature. Comparison to spectral standard stars observed with IUE shows similarities to O3-O7 V and early B…
Main-sequence B stars with strong winds in the core of NGC 6231.
Savage, B. D.; Massa, D.; Cassinelli, J. P.
Low-dispersion IUE observations of 13 main sequence B0 - 2 stars in the Sco OB1 association are presented. Eleven of these are in the rich open cluster NGC 6231. Most of the NGC 6231 stars have strong UV resonance lines which are inconsistent with either their spectral types or the rest of their UV spectra. A high-dispersion IUE spectrum of one of…
Changes in the ultraviolet spectrum of EG Andromedae.
Stencel, R. E.
Ultraviolet observations of EG Andromedae, a symbiotic star, are reported which clearly show pronounced eclipse-like effects on the high-temperature far-UV continuum. Continuum and emission-line variations with phase are reported and related to synoptic hydrogen alpha data. System parameters are characterized.
The central star of the planetary nebula Abell 78.
Feibelman, W. A.; Kaler, J. B.
The authors have studied the ultraviolet spectrum of the nucleus of Abell 78, one of the two planetaries known to contain zones of nearly pure helium. Abell 78 is strikingly similar in many respects to Abell 30, the other planetary with embedded helium knots. The ultraviolet-optical color temperature, which the authors tentatively identify with th…
IUE observations of the clusters of the Magellanic clouds.
Rich, R. M.; Persson, S. E.; Cohen, J. G.
IUE observations of 17 clusters in the Large Magellanic Cloud are presented. The derived ultraviolet colors become progressively redder as the cluster's classification in the scheme of Searle, Wilkinson, and Bagnuolo increases. With the aid of theoretical models of the integrated light of coeval clusters of varying ages, it is shown that the SWB c…
The detection of the F1 IIu-X1 +g system of diatomic carbon toward X Persei.
Lien, D. J.
The 0-0 vibrational band of the F1Pi(u)-X1Sigma(+)g electronic system of C2 has been detected with the IUE in the interstellar medium along the line of sight toward X Per. A column density of 3 (+ or - 1) x 10 to the 12th/f(00) per sq cm was derived by a profile fitting method. The lower limit for 0-0 band oscillator strength was determined from a…
Sigma Geminorum (K1 III + ?) : variability of the ultraviolet emission lines near conjunction.
Linsky, J. L.; Simon, T.; Ayres, T. R.
Far-ultraviolet IUE echelle spectra are reported of the moderate-period RS CVn system σ Geminorum. Despite the location of the red giant primary of σ Gem in a portion of the H-R diagram where cool stellar winds are common, no evidence is found for circumstellar absorption features or blueward asymmetries in the chromospheric O I emission cores. Ho…
X Cygni : duplicity, period stability and atmospheric velocity structure.
Evans, N. R.
Observations of X Cygni which can be used as tests of duplicity are discussed, including light variations, ultraviolet spectra, radial velocities, and period variations. IUE observations show no sign of a blue companion in the 2500-3000 A region, ruling out a single companion more massive than about 2.5 solar masses. The high luminosity of X Cygni…
Ultraviolet spectroscopy of the planetary nebula in the Fornax galaxy.
Gull, T. R.; Stecher, T. P.; Maran, S. P. +2 more
The planetary nebula in the Fornax dwarf spheroidal galaxy is carbon rich, according to calculations based on measurements of the 1909 A emission line doublet of semiforbidden C III obtained with the International Ultraviolet Explorer. The ratio N(C)/N(O) is approximately equal to 3.7, comparable to the largest reliably determined carbon/oxygen ra…
On interstellar absorption toward Cepheus OB2.
Hobbs, L. M.
A weak interstellar absorption line which can be identified as the forbidden line of Fe X 6375 A is observed in the spectrum of the A2 Ia star Nu Cep, which is a member of the Cepheus OB2 association. The equivalent width, width, and radial velocity of the line differ indistinguishably from those of similar absorption previously detected uniquely …