Extended atmospheres of AGB stars: modeling and measurement

M. J. Ireland*

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference proceeding contribution

Abstract

Encoded in the time- and wavelength-dependent properties of pulsating AGB stars are the underlying fundamental parameters of mass, composition and evolutionary state. However, the standard technique of placing stars on an HR diagram, even with the aid of pulsation periods, cannot be done easily for extended AGB stars because of the difficulty of defining a radius or temperature. The atmospheres of Mira variables are so extended that the optical depth unity radius can vary by a factor of similar to 3 over the energetically important region of the spectrum. Many important constituents in the radiative transfer are far from local thermodynamic equilibrium, and for the coolest stars, the process of dust formation and destruction requires a time-dependent model of grain growth. I will describe the challenges and some of the solutions to modeling these atmospheres, and will describe the utility of different kinds of observations in helping understand both fundamental parameters and chaotic processes in complex AGB atmospheres.

Original languageEnglish
Title of host publicationWhy galaxies care about AGB stars II
Subtitle of host publicationshining examples and common inhabitants
EditorsF. Kerschbaum, T. Lebzelter, R. F. Wing
Place of PublicationSan Francisco, CA
PublisherAstronomical Society of the Pacific
Pages83-93
Number of pages11
ISBN (Electronic)9781583817711
ISBN (Print)9781583817704
Publication statusPublished - 2011
Externally publishedYes
EventConference on Why Galaxies Care About AGB Stars II: Shining Examples and Common Inhabitants - Vienna, Austria
Duration: 16 Aug 201020 Aug 2010

Publication series

NameAstronomical Society of the Pacific Conference Series
PublisherAstronomical Society of the Pacific
Volume445

Conference

ConferenceConference on Why Galaxies Care About AGB Stars II: Shining Examples and Common Inhabitants
CountryAustria
CityVienna
Period16/08/1020/08/10

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