Undetected Binary Stars Bias the Observed Initial Mass Function

The initial mass function (IMF) is typically measured in young star-forming regions, which present a number of observational limitations. Unresolved binary stars in variably extincted and spatially extended regions are difficult to identify based on their position in an HR diagram, but they may bias the observed IMF. Most evidence indicates that the IMF is at least mostly universal, but some star forming regions, like Taurus, are discrepant with that universal IMF. This may be due to the presence of an unidentified population of binary stars. To investigate this hypothesis, we have carried out a synthetic low-resolution optical spectroscopic survey of a young star-forming region. Our simulated population includes unresolved close binaries, and we determine each system’s apparent effective temperature and luminosity using spectral fitting. Then, we use evolutionary models to infer an age and a mass for each system, allowing us to explore the apparent age and mass distribution produced by a population including unresolved multiplicity. We will present the initial results of this survey.