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Models Of Forbidden Line Emission Profiles From Axisymmetric Stellar Winds., R. Ignace, A. Brimeyer
Models Of Forbidden Line Emission Profiles From Axisymmetric Stellar Winds., R. Ignace, A. Brimeyer
Richard Ignace
A number of strong infrared forbidden lines have been observed in several evolved Wolf–Rayet (WR) star winds, and these are important for deriving metal abundances and testing stellar evolution models. In addition, because these optically thin lines form at large radius in the wind, their resolved profiles carry an imprint of the asymptotic structure of the wind flow. This work presents model forbidden line profile shapes formed in axisymmetric winds. It is well known that an optically thin emission line formed in a spherical wind expanding at constant velocity yields a flat-topped emission profile shape. Simulated forbidden lines are produced …
Microlensing Of Circumstellar Envelopes Iii. Line Profiles From Stellar Winds In Homologous Expansion., M. A. Hendry, R. Ignace, H. M. Bryce
Microlensing Of Circumstellar Envelopes Iii. Line Profiles From Stellar Winds In Homologous Expansion., M. A. Hendry, R. Ignace, H. M. Bryce
Richard Ignace
This paper examines line profile evolution due to the linear expansion of circumstellar material obsverved during a microlensing event. This work extends our previous papers on emission line profile evolution from radial and azimuthal flow during point mass lens events and fold caustic crossings. Both “flavours” of microlensing were shown to provide effective diagnostics of bulk motion in circumstellar envelopes. In this work a different genre of flow is studied, namely linear homologous expansion, for both point mass lenses and fold caustic crossings. Linear expansion is of particular relevance to the effects of microlensing on supernovae at cosmological distances. We …
The Polarization Signature From Microlensing Of Circumstellar Envelopes In Caustic Cossing Events., R. Ignace, J. E. Bjorkman, H. M. Bryce
The Polarization Signature From Microlensing Of Circumstellar Envelopes In Caustic Cossing Events., R. Ignace, J. E. Bjorkman, H. M. Bryce
Richard Ignace
In recent years, it has been shown that microlensing is a powerful tool for examining the atmospheres of stars in the Galactic bulge and Magellanic Clouds. The high gradient of magnification across the source during both small impact parameter events and caustic crossings offers a unique opportunity for determining the surface brightness profile of the source. Furthermore, models indicate that these events can also provide an appreciable polarization signal: arising from differential magnification across the otherwise symmetric source. Earlier work has addressed the signal from a scattering photosphere for both point mass lenses and caustic crossings. In a previous paper, …