Observation of the 94α and 148δ Hydrogen and 94α Helium Emission Lines in the Orion Nebula

1967 ◽  
Vol 149 ◽  
pp. L21 ◽  
Author(s):  
M. A. Gordon ◽  
M. L. Meeks
Keyword(s):  
Emission Lines ◽  
Orion Nebula ◽  
Helium Emission

scholarly journals Infrared helium emission lines from Cygnus X-3 suggesting a Wolf-Rayet star companion

Nature ◽  
1992 ◽  
Vol 355 (6362) ◽  
pp. 703-705 ◽  
Author(s):  
M. H. van Kerkwijk ◽  
P. A. Charles ◽  
T. R. Geballe ◽  
D. L. King ◽  
G. K. Miley ◽  
...  
Keyword(s):  
Emission Lines ◽  
Rayet Star ◽  
Helium Emission

Faint emission lines in the spectrum of the Orion Nebula and the abundances of some of the rarer elements

1992 ◽  
Vol 389 ◽  
pp. 305 ◽  
Author(s):  
Donald E. Osterbrock ◽  
Hien D. Tran ◽  
Sylvain Veilleux
Keyword(s):  
Emission Lines ◽  
Orion Nebula

scholarly journals Helium Emission Lines in the Type I[CLC]c[/CLC] Supernova 1999[CLC]cq[/CLC]

2000 ◽  
Vol 119 (5) ◽  
pp. 2303-2310 ◽  
Author(s):  
Thomas Matheson ◽  
Alexei V. Filippenko ◽  
Ryan Chornock ◽  
Douglas C. Leonard ◽  
Weidong Li
Keyword(s):  
Emission Lines ◽  
Type I ◽  
Helium Emission

scholarly journals New Models for Massive Star Populations in Young Starbursts: Summary of the Models and Applications

1999 ◽  
Vol 186 ◽  
pp. 285-285
Author(s):  
Daniel Schaerer ◽  
William D. Vacca
Keyword(s):  
Emission Line ◽  
Stellar Evolution ◽  
Massive Star ◽  
Optical Emission ◽  
Emission Lines ◽  
Evolutionary Synthesis ◽  
Stellar Spectra ◽  
New Models ◽  
Helium Emission ◽  
Line Strengths

Using the latest stellar evolution models, theoretical stellar spectra, and a compilation of observed emission line strengths from Wolf-Rayet (WR) stars, we have constructed evolutionary synthesis models for young starbursts (Schaerer & Vacca 1997; see also Schaerer 1996). We provide detailed predictions of UV and optical emission line strengths for both the WR stellar lines and the major nebular hydrogen and helium emission lines, as a function of several input parameters related to the starburst episode.

scholarly journals Commemorating John Dyson

2012 ◽  
Vol 10 (H16) ◽  
pp. 626-627
Author(s):  
Julian M. Pittard
Keyword(s):  
Early Life ◽  
Oral Examination ◽  
Emission Lines ◽  
Orion Nebula ◽  
Hii Region ◽  
Broad Emission ◽  
The University ◽  
University Of Manchester

John Dyson was born on the 7th January 1941 in Meltham Mills, West Yorkshire, England, and later grew up in Harrogate and Leeds. The proudest moment of John's early life was meeting Freddie Trueman, who became one of the greatest fast bowlers of English cricket. John used a state scholarship to study at Kings College London, after hearing a radio lecture by D. M. McKay. He received a first class BSc Special Honours Degree in Physics in 1962, and began a Ph.D. at the University of Manchester Department of Astronomy after being attracted to astronomy by an article of Zdenek Kopal in the semi-popular journal New Scientist. John soon started work with Franz Kahn, and studied the possibility that the broad emission lines seen from the Orion Nebula were due to flows driven by the photoevaporation of neutral globules embedded in a HII region. John's thesis was entitled “The Age and Dynamics of the Orion Nebula“ and he passed his oral examination on 28th February 1966.

Emission Lines in the Orion Nebula Near 8500 Å

1974 ◽  
Vol 86 ◽  
pp. 208 ◽  
Author(s):  
I. J. Danziger ◽  
Marc Aaronson
Keyword(s):  
Emission Lines ◽  
Orion Nebula

scholarly journals The Helium λ 10830 Line in Planetary Nebulae and the Orion Nebula

1968 ◽  
Vol 34 ◽  
pp. 74-75
Author(s):  
Arthur H. Vaughan
Keyword(s):  
Planetary Nebulae ◽  
Frame Of Reference ◽  
Emission Lines ◽  
Orion Nebula ◽  
Absorption Component ◽  
Frequency Redistribution ◽  
Upper Limit ◽  
Line Widths ◽  
And Shifts ◽  
Absorption Edges

Interferometric observations of profiles of He I λ 10830 emission lines in 11 planetary nebulae, and in selected regions of the Orion Nebula, are presented. In common with the Orion Nebula, the planetaries are shown to emit a P Cygni-like λ 10830 line, with the absorption component shifted toward the violet with respect to the laboratory wavelength in a frame of reference at rest in the centre of expansion of the gas. The emission components are shifted toward the red. In planetaries, the negative displacements of the absorption edges are, in general, approximately equal to the widths, β, of the emission components which, in turn, range from about 12 km/sec in IC 418 to about 28 km/sec in NGC 6210. The emission red-shift is about 0·7 β on the average, but individual shifts vary from 0·5 β in IC 2149 to 1·05 β in NGC 6826. The line widths and shifts tend to increase in nebulae with larger expansion velocities. In Orion, the absorption edges in the λ 10830 line coincide in velocity with those in the line He I λ 3888 observed against the spectra of the Trapezium stars. In planetaries, the absorption edges in the λ 10830 line appear qualitatively similar to those in the line He I λ 3888, but a coincidence in velocity could not be demonstrated.The observed profiles indicate that the nebulae are expanding, or that they contain expanding globules or filaments. Some form of circumnebular absorbing zone may be indicated. However, it is suggested that frequency redistribution associated with resonance-like scattering in a homogeneous expanding medium might in principle (even in the absence of stratification) account for the shifted λ 10830 profiles. (See Hummer, D.G. and Rybicki, G.B. (1968), Astrophys. J. Letters (in press), for a further discussion of this point.)No trace of He3 is evident from the profiles. Quantitative conclusions are uncertain without a model which reproduces most of the phenomena, but an upper limit of He3/He4 ≤ 0·05 or even 0·01 is suggested on the basis of conservative assumptions.

High‐Resolution Spectroscopy of Faint Emission Lines in the Orion Nebula

2000 ◽  
Vol 129 (1) ◽  
pp. 229-246 ◽  
Author(s):  
J. A. Baldwin ◽  
E. M. Verner ◽  
D. A. Verner ◽  
G. J. Ferland ◽  
P. G. Martin, ◽  
...  
Keyword(s):  
High Resolution ◽  
Emission Lines ◽  
High Resolution Spectroscopy ◽  
Orion Nebula
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