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C. Kahane M. Jura
Observatoire de
Grenoble, B.P. 53, F-38041 Grenoble Cedex 9, France
Department of Astronomy, University of California at Los
Angeles, Los Angeles CA 90024, USA
Abstract: We report high signal to noise millimeter wave observations of 11
nearby Semi-Regular variables, most with periods between 89 and 160
days, in the transitions (J=2-1) and (J=1-0) and
(J=2-1). The line profiles have been fitted by a model including
molecular excitation and radiative transfer and the derived envelope
properties (expansion velocity, mass loss rate, outer radius,
kinetic temperature distribution) are compared to the predictions of
theoretical models. The mass loss properties of this sample of
Semi-Regulars appear to be very similar with those of longer period
(300 P < 400 days) Miras, observed with the same
telescope. This result is consistent with the view that the
Semi-Regulars are overtone pulsators while the Miras are in the
fundamental pulsational mode. The pulsational mode does not
strongly affect the mass loss from the star.
Robert Lucas
Thu Mar 9 14:24:13 MET 1995