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The Impact of Dust/Gas Ratios on Chromospheric Activity in Red Giant and Supergiant Stars

Published online by Cambridge University Press:  30 December 2019

Kenneth G. Carpenter
Affiliation:
NASA Goddard Space Flight Center, Code 667, Greenbelt, MD, 20771, USA email: Kenneth.G.Carpenter@nasa.gov
Gioia Rau
Affiliation:
NASA Goddard Space Flight Center, Code 667, Greenbelt, MD, 20771, USA email: Kenneth.G.Carpenter@nasa.gov Dept. of Physics, Catholic University of America, USA email: gioia.rau@nasa.gov
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Abstract

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Stencel et al. (1986) analyzed IUE spectra of a modest set of cool stars and found that they continue to produce chromospheres even in the presence of high dust levels in their outer atmospheres. This reversed the previous results of Jennings (1973) and Jennings & Dyck (1972). We describe an on-going extension of these studies to a sample of stars representing a broader range in dust/gas ratios, using archival IUE and archival and new HST data on both RGB and AGB stars. Surface fluxes in emission lines will be analyzed to assess the chromospheric activity and obscuration by dust in each star, as those fluxes will follow a different pattern for reduced activity (temperature/density dependent) vs. dust obscuration (wavelength dependent). Wind characteristics will be measured by modeling of wind-reversed chromospheric emission lines.

Type
Contributed Papers
Copyright
© International Astronomical Union 2019 

References

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