Wolf-Rayet Mass-Loss Limits Due to Frequency Redistribution

Andrew J Onifer; Kenneth G Gayley

doi:10.1086/497322

Back

Wolf-Rayet Mass-Loss Limits Due to Frequency Redistribution

Journal article

Open access

Peer reviewed

Wolf-Rayet Mass-Loss Limits Due to Frequency Redistribution

Andrew J Onifer and Kenneth G Gayley

The Astrophysical journal, Vol.636(2 I), pp.1054-1066

01/10/2006

DOI: 10.1086/497322

Files and links (1)

url

https://arxiv.org/pdf/astro-ph/0510399View

Open Access

Abstract

The hypothesis that CAK-type line driving is responsible for the large observed Wolf-Rayet (W-R) mass-loss rates has been called into question in recent theoretical studies. The purpose of this paper is to reconsider the plausibility of line driving of W-R winds within the standard approach using the Sobolev approximation while advancing the conceptual understanding of this topic. Due to the multiple scattering required in this context, of particular importance is the role of photon frequency redistribution into spectral gaps, which in the extreme limit yields the statistical Sobolev-Rosseland (SSR) mean approximation. Interesting limits to constrain are the extremes of no frequency redistribution, wherein the small radii and corresponding high W-R surface temperature induces up to twice the mass-loss rate relative to cooler stars, and the SSR limit, whereby the reduced efficiency of the driving drops the mass flux by as much as an order of magnitude whenever there exist significant gaps in the spectral line distribution. To see how this efficiency drop might be sufficiently avoided to permit high W-R mass loss, we explore the suggestion that ionization stratification may serve to fill the gaps globally over the wind. We find that global ionization changes can only fill the gaps sufficiently to cause about a 25% increase in the mass-loss rate over the local SSR limit. Higher temperatures and more ionization states (especially of iron) may be needed to achieve optically thick W-R winds, unless strong clumping corrections eliminate the need for such winds.

Physics - Astrophysics of Galaxies

Physics - Cosmology and Nongalactic Astrophysics

Physics - Earth and Planetary Astrophysics

Physics - High Energy Astrophysical Phenomena

Physics - Instrumentation and Methods for Astrophysics

Physics - Solar and Stellar Astrophysics

Details

Title: Subtitle: Wolf-Rayet Mass-Loss Limits Due to Frequency Redistribution
Creators: Andrew J Onifer - Los Alamos National Laboratory
Kenneth G Gayley - University of Iowa
Resource Type: Journal article
Publication Details: The Astrophysical journal, Vol.636(2 I), pp.1054-1066
DOI: 10.1086/497322
ISSN: 0004-637X
eISSN: 1538-4357
Publisher: American Astronomical Society
Language: English
Date published: 01/10/2006
Academic Unit: Physics and Astronomy
Record Identifier: 9984429053502771

Metrics

5 Record Views

2 Times Cited - Web of Science