M DWARFS FROM HUBBLE SPACE TELESCOPE STAR COUNTS. V. THE Ⅰ-BAND LUMINOSITY FUNCTION

摘要

We derive the disk Ⅰ-band luminosity function from the Zheng et al. sample of ～1400 disk M dwarfs observed with the Hubble Space Telescope. We adopt a Galactic-height-dependent color-magnitude relation to account for the metallicity gradient above the Galactic plane. The resultant Ⅰ-band luminosity function peaks at M_Ⅰ～9.5 and drops sharply toward M_Ⅰ～10.5.