High-Excitation Emission Lines in the Far-Ultraviolet Spectrum of the Late A Star α Cephei

1998 ◽  
Vol 500 (1) ◽  
pp. L37-L39 ◽  
Author(s):  
Theodore Simon ◽  
Thomas R. Ayres
Keyword(s):  
Ultraviolet Spectrum ◽  
Emission Lines ◽  
High Excitation ◽  
Far Ultraviolet

scholarly journals Mass loss from Eta Carinae

1979 ◽  
Vol 83 ◽  
pp. 47-50
Author(s):  
C. D. Andriesse ◽  
R. Viotti
Keyword(s):  
Turbulent Flow ◽  
Mass Loss ◽  
Large Mass ◽  
Ultraviolet Spectrum ◽  
High Excitation ◽  
High Luminosity ◽  
Hydrogen Burning ◽  
Eta Carinae ◽  
Hot Zone

This high luminosity (5 × 106 L⊙) star since 1840 is losing mass at the rate of 7.5 × 10−2 M⊙ per year. The large mass loss could be the result of vibrational instabilities produced in the CNO hydrogen burning phase of a very massive (160 M⊙) star. The presence of high excitation lines in the ultraviolet spectrum of Eta Car suggests the idea of a hot zone excited by dissipation of the supersonic turbulent flow.

scholarly journals The IUE Ultraviolet Spectrum of PC 11

1993 ◽  
Vol 155 ◽  
pp. 398-398 ◽  
Author(s):  
M. Parthasarathy ◽  
S.R. Pottasch ◽  
J. Clavel
Keyword(s):  
Short Wavelength ◽  
Planetary Nebula ◽  
Significant Variation ◽  
Central Star ◽  
Ultraviolet Spectrum ◽  
Emission Lines ◽  
Symbiotic Star ◽  
Iras Source ◽  
Long Wavelength ◽  
Cold Dust

PC 11 (HD 149427, PK 331-5 1) is classified as a young planetary nebula with strong OIII 4363Å and a Zanstra temperature of TZ = 27000K. It is also classified as (D′ — type) yellow symbiotic star with A — F type companion. It is an IRAS source with detached cold dust with far intrared (IRAS) colours similar to planetary nebulae. The IUE short wavelength (SWP) spectra show emission lines due to OIII] (1661/1666Å). NIII] (1746/1754Å) CIII] (1907/1909Å). The OIII] and NIII] emission lines show significant variation. Variation in the strength of CIII] is not very significant. The strength of OIII] has decreased and NIII] has increased. The long wavelength (LWP) spectrum shows stellar continuum (A-F) and absorption lines due Mg II 2800Å feature. It also show emission lines at 2772Å (?) 3133Å −3140Å (very strong) (OIII, [FeV], 3209Å (He II?) ([FEII]). The variation in the strength of emission line due OIII] and NIII] and the presence of stellar continuum (A-F) suggests that the central star of PC 11 is a binary.

scholarly journals The Far‐Ultraviolet Spectrum of the Io Plasma Torus

2004 ◽  
Vol 601 (1) ◽  
pp. 583-591 ◽  
Author(s):  
Paul D. Feldman ◽  
Darrell F. Strobel ◽  
H. Warren Moos ◽  
Harold A. Weaver
Keyword(s):  
Ultraviolet Spectrum ◽  
Plasma Torus ◽  
Far Ultraviolet ◽  
Io Plasma Torus

scholarly journals ISO Observations of AGN and Ultraluminous IR Galaxies

1998 ◽  
Vol 11 (2) ◽  
pp. 1131-1133 ◽  
Author(s):  
Alan F. M. Moorwood
Keyword(s):  
Ionization Potential ◽  
Elliptical Galaxy ◽  
Emission Lines ◽  
Spectral Energy ◽  
High Excitation ◽  
Low Resolution ◽  
Energy Distributions ◽  
Diagnostic Features ◽  
Wide Range ◽  
First Time

All the ISO instruments are contributing to the study of activity in galaxies of essentially all types. Although AGN's as such are pointlike, the beautiful CAM image of CenA shown by Catherine Cesarsky has given us the clearest view so far of its visually obscured nucleus and surrounding spiral disc embedded in an elliptical galaxy. The CAM CVF is also providing spectral images of the PAH features and important diagnostic ionic lines (e.g [NeII] and [NeIII]) in the circumnuclar regions of AGN and merging starburst systems (Vigroux et al., 1996). PHT is providing detailed spectral energy distributions over the complete 2.5-240µm range and PHTS is proving invaluable for assembling a catalogue of low resolution (R ⋍ 90) galaxy spectra covering the 6-12µm PAH features. SWS and LWS are generating higher resolution (R ⋍ 2000-200) spectra over the range 2.5-200µm such as that shown in Fig. 1. of the Circinus galaxy which exhibits both AGN and starburst activity and well illustrates the wide range of diagnostic features, many seen for the first time, accessible to ISO studies of galaxies. It shows the overall continuum with a peak around 100µm; PAH features and Si absorption which dominate the spectrum around 10µm; H recombination lines; H2 pure rotational emission lines; low ionization potential ionic lines excited by starburst activity and high excitation lines (up to ⋍ 300eV) excited by the visually obscured AGN.

Hopkins ultraviolet telescope observations of the far-ultraviolet spectrum of NGC 4151

1992 ◽  
Vol 392 ◽  
pp. 485 ◽  
Author(s):  
G. A. Kriss ◽  
A. F. Davidsen ◽  
William P. Blair ◽  
C. W. Bowers ◽  
W. V. Dixon ◽  
...  
Keyword(s):  
Ultraviolet Spectrum ◽  
Ngc 4151 ◽  
Far Ultraviolet

Detection of Far-Ultraviolet High-Excitation Line Emission and Lyman- beta Absorption in the Gravitational Lens Q0957+561

1993 ◽  
Vol 417 ◽  
pp. L57 ◽  
Author(s):  
A. G. Michalitsianos ◽  
J. Nichols-Bohlin ◽  
F. C. Bruhweiler ◽  
D. Kazanas ◽  
Y. Kondo ◽  
...  
Keyword(s):  
Line Emission ◽  
Gravitational Lens ◽  
High Excitation ◽  
Excitation Line ◽  
Far Ultraviolet
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