Gayley, Kenneth

Contact Email: kenneth-gayley@uiowa.edu
Institute: University of Iowa
Subject Area: Stellar Atmospheres, Circumstellar Material
Waveband: Multi-wavelength
Technique: Spectroscopy
Presentation: Poster Display
Title: Analytic LIne-Profile Diagnostics in Partial Redistribution with Continuum Absorption
Abstract: The comoving-frame partially coherent scattering (CPCS) approximation is a heuristic approach to modeling partially coherent resonance-line scattering. It is analytic, conceptually motivated, and easy to apply. Here, it is extended to include the effects of continuum or dust absorption. As usual for resonance lines, a key process is Doppler diffusion, whereby photons created in the line core reach wing frequencies via the gradual accumulation of thermal Doppler shifts over many scatterings. A semi-analytic conceptual approximation is derived, to reveal the mechanisms by which background opacity alters resonance-line formation and profile diagnostics in effectively thick static atmospheres. This is especially pertinent to low-density environments with appreciable continuous absorption, and the subsequent breakdown of the Wilson-Bappu effect.