Young Star Spectroscopic Binary Mass Ratios

Mass is the most fundamental stellar parameter. For a given composition, a star's mass determines the character and duration of its entire life and the manner of its death. Accurate and precise masses comprise the underpinnings of stellar astrophysics, from the mass-luminosity relation, to models of pre-main sequence evolution. Mass ratio distributions of young stars directly test models of binary star formation. I will describe the progress made over the past decade in using infrared, high-resolution spectroscopy of young spectroscopic binaries in nearby star forming regions to determine pre-main sequence stellar mass ratios and masses, highlighting the past and ongoing contributions of many student collaborators. This presentation will include the most up to date results for the dynamically determined mass ratio distribution, case studies of the most intriguing young systems, and a preview of a new program to triple the number of precisely known pre-main sequence spectroscopic binary mass ratios.