Infrared spectroscopy of five short-period Miras and the peculiar Mira Z Ophiuchi

Time-series 2.0-2.5 mu m infrared spectra have been observed for Miras with periods less than 200 days. Some of these stars are high velocity and meta l poor. We have also observed the peculiar, possibly metal-poor Mira, Z Oph . Velocities, excitation temperatures, and C-12/C-13 have been determined f or these stars. These results are compared with similar data for bright, fi eld Miras. We find Z Oph to be a metal-poor Mira of very low mass-loss rate . All Miras regardless of period, metallicity, or chemical abundance have t he same pulsation velocity amplitude. The mode of pulsation is discussed.