Estimating distances to AGB stars using IR data

The BAaDE project has delivered line-of-sight velocities to more than 10,000 AGB stars in the Milky Way. To incorporate these velocities into dynamical models, and to understand whether there are multiple dynamical models and to distinguish different AGB populations, distance estimates are crucial to determine 3D positions as well as mass loss rates and luminosities. For AGB stars in particular, Gaia parallaxes have been shown to be prone to large error. Therefore, we investigate an alternative method to estimate the distances for the AGB stars, utilizing the rich auxiliary infrared data sets available for these infrared-bright targets. The method is based on the assumption that stars with intrinsically similar properties (metallicity, initial mass, etc.) produce similar spectral energy distributions (SEDs) with similar luminosity. Through distance-calibrated template SEDs distances are estimated. We here discuss the results for AGB stars belonging to the BAaDE survey sample using templates with distances calibrated with VLBI parallaxes. As VLBI parallaxes are only known for a handful of sources, the resulting templates only cover a small subset of the BAaDE sample. Additional methods to derive suitable templates will therefore also be required. We will also mention potential challenges that this method faces, such as variability.