Poster Abstracts

Name/Affiliation:  Neda Hejazi (York University)

Title:  M dwarf Metallicity Distribution and Galactic Chemical Evolution

Neda Hejazi (York University) Michael. M. De Robertis (York University) Peter.C. Dawson (Trent University) Based on 24 carefully selected M dwarfs and the most recent BT-Settl model atmospheres, we present new photometric calibrations to estimate metallicity and effective temperature of dwarf stars with spectral types ranging from K7 to M3. Using these calibrations, the metallicity and temperature distributions of a volume-limited sample, including over 450,000 late-type K and early-type M dwarfs from the Sloan Digital Sky Survey (SDSS) and the Two-Micron All Sky Survey (2MASS), are studied. The results show a decrease in temperature with increasing metallicity, which is consistent with theoretical models. The recently measured FGK dwarf metallicity distributions are in better agreement with our M dwarf distribution than that from the previous study. There is a scarcity of metal-poor stars in the M dwarf metallicity distribution as compared to the distribution predicted by the “Simple Closed Box Model”, implying the existence of the M dwarf Problem", similar to the previously known G and K dwarf problems.