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Full-Text Articles in Stars, Interstellar Medium and the Galaxy
"Wcfields": A Magnetic Rotating Stellar Wind Model From Wind Compression Theory., R. Ignace, J. P. Cassinelli, J. E. Bjorkman
"Wcfields": A Magnetic Rotating Stellar Wind Model From Wind Compression Theory., R. Ignace, J. P. Cassinelli, J. E. Bjorkman
Richard Ignace
A stellar wind model for a magnetic rotating star is presented. We use the semianalytic wind compression model that predicts the two-dimensional geometry of outflows from rotating stars and consider the addition of a magnetic field. In the limit of weak magnetic fields, in such a way that the fields are unimportant in accelerating the flow, the wind compression model can be used to predict the magnetic field distribution throughout the wind, which is shown to follow the mass flux distribution. A compression of field lines near the equator results as the flow of material from higher latitudes brings magnetic …
Emission Line Profile Shapes From Anisotropic Scattering In Planar Equatorial Disks., R. Ignace
Emission Line Profile Shapes From Anisotropic Scattering In Planar Equatorial Disks., R. Ignace
Richard Ignace
The consequences of anisotropic resonance line scattering for the emission profiles of equatorial disks are considered. In particular the opportunity to infer the disk velocity field owing to the anisotropic scattering is discussed. Analytic expressions for the profile shapes are derived for the cases of constant expansion and rotation, and numerical results are given for more realistic disk velocity fields of linear expansion and Keplerian rotation. The essential result is that the anisotropic line scattering produces a different profile signature in expanding disks as compared to rotating disks, owing to the difference in the isovelocity pattern of the two cases …
Inference Of Steady Stellar Wind V(R) Laws From Optically Thin Emission Lines Iii. Inversion Of Total Line Intensity Distributions., R. Ignace, J. C. Brown, J. E. Milne, J. P. Cassinelli
Inference Of Steady Stellar Wind V(R) Laws From Optically Thin Emission Lines Iii. Inversion Of Total Line Intensity Distributions., R. Ignace, J. C. Brown, J. E. Milne, J. P. Cassinelli
Richard Ignace
The variation with wavelength for a sequence of total intensities of stellar wind lines is considered as a basis for deriving the wind velocity law v(r). In particular, we focus on the case where the continuum formation in the wind is dominated by the free-free opacity so that the inner radius increases with wavelength, as is realized in some massive winds like those of the Wolf-Rayet stars. The line emission in the wind occurs exterior to the continuum photosphere, hence lines observed at different wavelengths probe different regions of the wind acceleration. A major consequence of these physical conditions is …
A Re-Evaluation Of Profile Shapes From Resonance Line Scattering In Spherical Stellar Winds., R. Ignace
A Re-Evaluation Of Profile Shapes From Resonance Line Scattering In Spherical Stellar Winds., R. Ignace
Richard Ignace
It is common to treat the scattering of light by resonance lines as isotropic, but in fact it has been known for some time that general resonance line scattering is partially isotropic and partially dipolar, the relative strength of the two components depending on the specific transition. As a result, the profile shapes of lines that scatter with strong dipole distributions could in principle differ markedly from those that scatter isotropically. This paper explores the consequences of general resonance line scattering in spherically symmetric stellar envelopes. As a simplified example, a resonance line profile arising in a constant expansion wind …
Inference Of Steady Stellar Wind V(R) Laws From Optically Thin Emission Lines Ii. Occultation Effects And The Determination Of Intrinsic Stellar Properties., R. Ignace, J. C. Brown, L. L. Richardson, J. P. Cassinelli
Inference Of Steady Stellar Wind V(R) Laws From Optically Thin Emission Lines Ii. Occultation Effects And The Determination Of Intrinsic Stellar Properties., R. Ignace, J. C. Brown, L. L. Richardson, J. P. Cassinelli
Richard Ignace
This paper extends previous work on the inversion of line profiles to obtain wind velocity laws to a case that includes the occultation of light from the far side of the star. The velocity law v(r) is assumed to be from a wind that is steady and spherically symmetric. The wind is also assumed to be optically thin in the emission line profile. The major result here is the derivation of an analytic inversion formula. The effects of stellar occultation are shown to produce a significant change in the analysis from paper I, and by accounting for the occultation, the …