Presentation #305.18 in the session Stars, Cool Dwarfs, Brown Dwarfs — iPoster Session.
After decades of brown dwarf discovery and follow-up, we are now at the point where the functional form of the mass distribution for the 20-parsec region can be measured, which will serve as a constraint on the theory. For brown dwarfs, the lack of a correlation between an observable parameter (such as luminosity, spectral type, or color) and mass has long been a thorn in the side of astronomers. Unlike the main sequence, which enjoys a clear luminosity-to-mass correlation providing a straightforward mass function, estimates for brown dwarfs must be procured through proxy measurements and theoretical models. We utilize various forms of the mass function for brown dwarfs, together with a slew of assumed birthrate functions. Our simulated brown dwarf populations are drawn from one of these mass functions paired with one of these birthrate functions. We find the temperature of each simulated star using theoretical evolutionary models and arrive at the corresponding temperature distribution for our population. We determine the best fit of the observational data to these temperature distributions, which in turn reveals the most likely mass function. As Burgasser (2004) has shown – and as we have corroborated – the birthrate function has a far lesser impact than the mass function on the form of the temperature distribution. Findings will be presented at the conference. Using our aforementioned methods, we will also present findings on the width and location of the subdwarf temperature gap.