The massive Wolf-Rayet binary WR 98 (WN7/WC+08-9)

We present the discovery of OB type absorption lines superimposed to the emission line spectrum, and the first double-lined orbital elements, for the massive Wolf-Rayet binary WR 98 (HDE 318016, WN7/C+08-9), a spectroscopic binary in a circular orbit with a period of 47.825 d. The semi-amplitudes of the orbital motion of the emission lines differ from line to line, indicating a mass ratio in the range q ≡ MWR/MOB = 1–1.8.

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Variability of the Emission Line Spectrum of the Nucleus of Seyfert Galaxy NGC 1275

Symposium - International Astronomical Union ◽

10.1017/s0074180900024542 ◽

1974 ◽

Vol 58 ◽

pp. 341-345

Author(s):

I. Pronik

Keyword(s):

Emission Line ◽

Seyfert Galaxy ◽

Emission Lines ◽

Line Spectrum ◽

Spectroscopic Observations ◽

Emission Line Spectrum ◽

Ngc 1275

Recent spectroscopic observations of the nucleus of NGC 1275, together with results from earlier workers, confirm the variability of the emission lines and indicate corresponding variations in the electron temperatures and densities of different zones. These changes may be associated with the microwave outbursts from this source.

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The Ionization of Novae Ejecta

International Astronomical Union Colloquium ◽

10.1017/s0252921100068664 ◽

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.

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The unusual emission line spectrum of I Zw 1

Proceedings of the International Astronomical Union ◽

10.1017/s1743921304002248 ◽

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

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

International Astronomical Union Colloquium ◽

10.1017/s025292110010510x ◽

1987 ◽

Vol 93 ◽

pp. 371-376 ◽

Cited By ~ 2

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.

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A Study of the Orbital and Intrinsic Variability of the Double-Lined Spectroscopic Binary β Centauri

International Astronomical Union Colloquium ◽

10.1017/s025292110001561x ◽

2002 ◽

Vol 185 ◽

pp. 86-87

Author(s):

M. Ausseloos ◽

C. Aerts ◽

K. Uytterhoeven

Keyword(s):

High Resolution ◽

Orbital Motion ◽

High Signal ◽

Mass Ratio ◽

Eccentric Orbit ◽

Intrinsic Variability ◽

Signal To Noise ◽

Orbital Parameters ◽

Spectroscopic Binary ◽

First Time

AbstractWe introduce our observational study of the orbital motion of β Cen. Using 463 high signal-to-noise, high-resolution spectra obtained over a timespan of 12 years it is shown that the radial velocity of β Cen varies with an orbital period of 357.0 days. We derive for the first time the orbital parameters of β Cen and find a very eccentric orbit (e = 0.81) and similar component masses with a mass ratio M1/M2 = 1.02. Both the primary and the secondary exhibit periodic line-profile variations.

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

Symposium - International Astronomical Union ◽

10.1017/s0074180900095784 ◽

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.

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Photometry of AM Her Stars – Line and Continuum Emission

International Astronomical Union Colloquium ◽

10.1017/s0252921100076132 ◽

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).

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