Oxygen-rich Mira variables: near-infrared luminosity calibrations

Abstract

Hipparcos astrometric and kinematical data of oxygen-rich Mira variables are used to calibrate absolute near-infrared magnitudes (broad-band K and narrow-band photometric measurements at 1.04 x 10^(-6)m) and kinematic parameters. Three distinct classes of stars with different kinematics and scale height have been identified. The two most significant groups present characteristics close to the ones usually assigned to extended/thick disk-halo population and old disk population respectively, and thus they might differ by their metallicity abundance. Two parallel period-luminosity relations are found in K as well as in 104, one for each significant population. The shift between these relations is interpreted as the consequence of the effects of metallicity abundance on the luminosity.