Search Publications
Ultraviolet continuum and H2 fluorescent emission in Herbig-Haro objects 43 and 47.
Schwartz, R. D.
IUE short wavelength spectra are presented for the low excitation Herbig-Haro objects HH 43 and HH 47. In the former, several emission lines in the Lyman band of H2 from an excited state are observed which are due to fluorescence from the H Ly-alpha line pumping a lower state (that is in turn excited by a low-velocity shock wave). No evidence of h…
Analysis of nebulosity in the planetary nebula NGC 40.
Seaton, M. J.; Clegg, R. E. S.; Torres-Peimbert, S. +1 more
Optical and IUE spectra of a bright region of nebulosity in the planetary nebula NGC 40 have been combined for an analysis of the physical conditions and abundances in the nebula. Resulting abundances are typical of planetary nebulae and indicate that the nebulosity does not share the extreme abundances of the Wolf-Rayet WC8 central star. The cont…
Reddening indicators for quasars and Seyfert 1 galaxies.
Grandi, S. A.
It is pointed out that a determination of the reddening caused by intervening dust is a prerequisite to understanding the astrophysics of the broad line emission in quasars and their close cousins Seyfert 1 galaxies. Previous discussions of the reddening question have tended to be incomplete. The present investigation represents an attempt to asse…
The symbiotic star H1-36.
Allen, D. A.
The high-excitation emission-line star H1-36 is investigated using optical and infrared spectrophotometry. It is established that H1-36 may be classified as a symbiotic star due to the presence of a variable M giant. The observations are analyzed in terms of the usual binary model for symbiotic stars in which an unseen star is heated by accretion …
IUE observations of W UMa-type stars.
Vilhu, O.; Rucinski, S. M.
IUE (International Ultraviolet Explorer) low-resolution SWP images of the contract binaries 44i Boo, VW Cep, W UMa, V566 Oph, AW UMa, V502 Oph, Epsilon CrA, RR Cen and the very close non-contact binary ER Vul have been studied. The results are compared with other UV and soft X-ray data and it is found that the stellar activity within this group is…
The binary central star of the planetary nebula LT-5.
Feibelman, W. A.; Kaler, J. B.
The authors have found with the IUE that the true central star of the giant planetary Longmore-Tritton 5 (339+88°1) is a binary companion to the G5 star SAO 82570. The slope of the energy distribution curve indicates that the star may be one of the hottest known. The Mg II doublet associated with the G star is very strong, consistent with the exis…
The ultraviolet variability of NGC 3783.
Willis, A. J.; Wilson, R.; Barr, P.
The results of three years of monitoring the spectral variability of the type 1 Seyfert galaxy NGC 3783 with IUE spacecraft instrumentation are reported. Techniques for fitting power laws to the observed wavebands are described, noting the monitoring was carried out in the 1150-3150 A region. The continuum was found to vary by a factor of ten over…
The planetary nebula IC 3568 : a model based on IUE observations.
Feibelman, W. A.; Harrington, J. P.
The planetary nebula IC 3568 has been observed at both low and high dispersion with the IUE satellite. The spectrum of the star shows strong P Cygni profiles due to an 1840 km/s stellar wind. The nebular spectrum shows lines of He II, semi-forbidden C III, C IV, semi-forbidden N III, and semi-forbidden O III. The spatial distribution of the gas ha…
R66 (Aeq), an LMC B Supergiant with a Massive, Cool and Dusty Wind
Stahl, O.; Leitherer, C.; Bastian, U. +3 more
The LMC's peculiar emission line star R 66 (Aeq) is studied by means of high dispersion spectroscopy and UBV and JHKLM photometry, from which a model is derived which consists of a massive, luminous B-type supergiant surrounded by a dense, cool expanding envelope and a circumstellar dust shell whose temperature is 1100 K at its inner edge. R 66 be…
The pulsation properties of DB white dwarfs : a preliminary analysis.
Hansen, C. J.; Winget, D. E.; Fontaine, G. +2 more
Preliminary numerical results are given for the nonradial g-mode pulsation properties of evolutionary DB white dwarf models, where the solutions include the fully nonadiabatic equations for modes corresponding to the spherical harmonic index l = 1-3. For each of the model sequences examined, a nonradial g-mode instability strip approximately 3000 …