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We have discovered narrow emission lines in the SWS full grating spectra
of a number of oxygen-rich mira variables. These lines are only detected
in stars that also show the 13um dust feature in their spectra. This dust
feature has been attributed to some form of aluminum oxide. Since shocks
in mira atmospheres are supposed to play an important role in the dust
formation close to the star, where aluminum oxide is supposed to freeze
out, the 13um feature and the emission lines may be related to the
presence of shocks in the extended mira atmosphere.
In this proposal, we want to obtain high resolution SWS spectra of a sample
of bright mira variables that show the 13um feature with the aim of
(1) detecting these emission lines in the spectrum of more miras
(2) confirming the correlation between the presence of the 13um feature and
these narrow emission lines.
OBSID  : TDEJONG
PROPID : AGBSTAR2