A Reassessment of the IUE Emission Line Spectrum of the Planetary Nebula NGC 5189 and Its Central Star

1997 ◽  
Vol 109 ◽  
pp. 982 ◽  
Author(s):  
W. Feibelman
Keyword(s):  
Emission Line ◽  
Planetary Nebula ◽  
Central Star ◽  
Line Spectrum ◽  
Emission Line Spectrum

scholarly journals The very fast evolution of Sakurai's object

2016 ◽  
Vol 12 (S323) ◽  
pp. 380-381 ◽  
Author(s):  
G. C. Van de Steene ◽  
P. A. M. van Hoof ◽  
S. Kimeswenger ◽  
A. A. Zijlstra ◽  
A. Avison ◽  
...  
Keyword(s):  
High Resolution ◽  
Emission Line ◽  
Planetary Nebula ◽  
Temporal Evolution ◽  
Optical Emission ◽  
Central Star ◽  
Evolutionary Models ◽  
Thermal Pulse ◽  
Emission Line Spectrum ◽  
Fast Evolution

AbstractV4334 Sgr (a.k.a. Sakurai's object) is the central star of an old planetary nebula that underwent a very late thermal pulse a few years before its discovery in 1996. We have been monitoring the evolution of the optical emission line spectrum since 2001. The goal is to improve the evolutionary models by constraining them with the temporal evolution of the central star temperature. In addition the high resolution spectral observations obtained by X-shooter and ALMA show the temporal evolution of the different morphological components.

The Symbiotic Star H1-36

1983 ◽  
Vol 5 (2) ◽  
pp. 211-213 ◽  
Author(s):  
David A. Allen
Keyword(s):  
Emission Line ◽  
Planetary Nebula ◽  
Line Spectrum ◽  
Symbiotic Star ◽  
Symbiotic Stars ◽  
High Excitation ◽  
Infrared Excess ◽  
Emission Line Spectrum ◽  
Definition Of ◽  
Meaningful Definition

Since its discovery by Haro (1952) the star H1-36 has been catalogued as a planetary nebula despite its extremely high-excitation emission-line spectrum (e.g. [Fe VII], [Ne V]) and its imposing, variable infrared excess. Because its optical spectrum resembled those of many symbiotic stars, I have persistently classified H1-36 as such. A meaningful definition of a symbiotic star would necessarily include both the high-excitation emission-line spectrum and the presence of a cool (usually M-type or Mira) giant.

scholarly journals The Ionization of Novae Ejecta

1990 ◽  
Vol 122 ◽  
pp. 215-227
Author(s):  
R.E. Williams
Keyword(s):  
Emission Line ◽  
White Dwarf ◽  
Line Spectrum ◽  
Ionized Gas ◽  
Grain Formation ◽  
Emission Line Spectrum ◽  
Pass Through

AbstractNovae ejecta pass through four distinct phases of evolution of the emission-line spectrum, caused by different ionization characteristics of the shell. These include a neutral (I), an auroral (II), a coronal (III), and a nebular (IV) phase. Photoionization from the contracting photosphere of the hot white dwarf is the source of the ionization, including the highly ionized coronal phase. Changing emission line ratios in certain novae that develop dust are caused by condensation of grains from the gas, and can be used to determine the composition of the dust. In V1370 Aql, substantial silicate grain formation appears to have taken place, probably within the ionized gas.

scholarly journals The unusual emission line spectrum of I Zw 1

2004 ◽  
Vol 2004 (IAUS222) ◽  
pp. 271-274
Author(s):  
Monique Joly ◽  
M.-P. Véron-Cetty ◽  
P. Véron
Keyword(s):  
Emission Line ◽  
Line Spectrum ◽  
Emission Line Spectrum

scholarly journals The May 1985 Superoutburst of OY Carinae: II. Phase-Resolved IUE Spectroscopy and Exosat Observations

1987 ◽  
Vol 93 ◽  
pp. 371-376 ◽  
Author(s):  
B.J.M. Hassall ◽  
T. Naylor ◽  
G.T. Bath ◽  
P.A. Charles ◽  
G. Sonneborn ◽  
...  
Keyword(s):  
Emission Line ◽  
Line Spectrum ◽  
X Ray ◽  
Dwarf Nova ◽  
Uv Emission ◽  
Emission Line Spectrum ◽  
Coronal Region

AbstractWe present ultraviolet and X-ray observations of the eclipsing SU UMa dwarf nova OY Car early in the decline from a superoutburst. From the UV emission line spectrum and lack of X-ray eclipse, we deduce the presence of an extended coronal region.

scholarly journals Models for the Emission-Line Spectra of the Low-Excitation Herbig-Haro Objects

1987 ◽  
Vol 115 ◽  
pp. 346-347
Author(s):  
Michael A. Dopita ◽  
Saul Caganoff ◽  
Richard D. Schwartz ◽  
Martin Cohen
Keyword(s):  
Emission Line ◽  
Theoretical Description ◽  
Line Spectrum ◽  
High Excitation ◽  
Two Photon ◽  
Shock Models ◽  
Uv Excess ◽  
Hh Objects ◽  
Emission Line Spectrum

The class of Low-Excitation Herbig-Haro Objects are characterised by [SII] and [OI] lines which are comparable in strength to H-Alpha, by [NI] lines that are comparable to H-Beta, relatively weak [NII] and [OII] lines, little or no [OIII] emission and a very strong blue-UV “excess”. This blue and UV continuum in low-excitation HH Objects was noted as a problem by Brugel, Böhm and Mannery (1981), Ortalani and D'Odorico (1980) and Böhm, Böhm-Vitense and Brugel (1981). The first suggestion that it results from collisionally enhanced Hydrogen two-photon (2q) continuum was by Dopita (1981). The subsequent observations of Dopita, Binette and Schwartz (1982) proved that this was indeed the case. However, although very close correlations between this enhancement and the emission-line spectrum were found, a fair theoretical description could only be obtained for very youthful shock models with ages of order 30 years. However, there seems to be no reason why low excitation HH shocks should be much younger than the high excitation shocks.

scholarly journals Photometry of AM Her Stars – Line and Continuum Emission

1979 ◽  
Vol 53 ◽  
pp. 324-328
Author(s):  
Paula Szkody
Keyword(s):  
Emission Line ◽  
White Dwarf ◽  
Main Sequence ◽  
Close Binary ◽  
Line Spectrum ◽  
Continuum Emission ◽  
Late Type ◽  
Emission Line Spectrum ◽  
Orbital Periods

The 4 known AM Her stars or polars (AM Her, ANUMa, W Pup, and 2A0311-227) are characterized by large circular polarizations of 10-35%, (Tapia 1977a, b, Krzeminski and Serkowski 1977), an emission line spectrum with strong H and He lines (Crampton and Cowley 1977, Greenstein et al. 1977), complex photometric variations (Szkody 1978, Priedhorsky and Krzeminski 1978, Warner & Nather 1972), long term high and low states and short orbital periods (80-180 min.). Models of these systems envision a close binary containing a magnetic white dwarf primary (B ~ 108G) and late type main sequence secondary transferring material into an accretion funnel over one or both poles of the white dwarf (Stockman et al. 1977, Lamb & Masters 1979, Liebert et al. 1978).

Calculation of the ionization and emission line spectrum of the T Tau nebula

Astrophysics ◽  
1979 ◽  
Vol 15 (2) ◽  
pp. 188-194
Author(s):  
V. V. Golovatyi ◽  
I. V. Shpychka ◽  
O. S. Yatsyk
Keyword(s):  
Emission Line ◽  
Line Spectrum ◽  
Emission Line Spectrum ◽  
T Tau

The Emission-Line Spectrum of 3c 273

1967 ◽  
Vol 148 ◽  
pp. 695 ◽  
Author(s):  
E. J. Wampler ◽  
J. B. Oke
Keyword(s):  
Emission Line ◽  
Line Spectrum ◽  
Emission Line Spectrum
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