Cool Stars 14 - Submitted Abstract # 348
This version created on 05 October 2006

Cool Stars Sing the Blues -- The Encore


Donald Luttermoser, East Tennessee State University

High-dispersion spectra of cool red giant stars in the blue and violet
are presented.  The spectra were obtained over a six-year time period
with the stellar spectrograph of the McMath-Pierce Telescope on Kitt
Peak.  Both N-type carbon stars and M-type oxygen-rich stars are
presented from 3900  to 4600  A, with the M-type stars containing both
semiregular and Mira-type variables.  The dominant absorption features
in these stars at these wavelengths result primarily from neutral
metals, especially iron, and the CH and CN diatomic molecules.  The
Miras also show strong emission lines during some of their pulsation
cycle.  Many of these emission lines result from fluorescence from the
Mg II h & k lines in the UV.  For these fluoresced features,
comparisons are made between the Miras and the semiregular carbon-rich
and oxygen-rich variables.  Mg II profiles show a substantial
circumstellar (CS) absorption from neutral metals especially Fe I in
the Miras and the carbon-rich semiregulars.  The oxygen-rich
semiregulars show no hint of fluorescence in the optical as would be
expected from the appearance of their unobscured Mg II profiles.
Strangely, these "fluoresced" lines in the carbon stars show no hint
of emission despite the large CS absorption by their "pumps" in the Mg
II lines.  This poster discusses the reasons for the lack of this
fluoresced emission in these stars.  

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