Identifying Widely Separated Co-moving Brown Dwarfs

Brown dwarfs are cold substellar objects which are theorized to form through direct collapse, similar to stars, but do not have enough mass to sustain hydrogen fusion. Because brown dwarfs lack a stable energy generating mechanism, they cool over time as they radiate the initial heat from their formation away, and therefore do not follow a simple temperature-mass relationship. Brown dwarfs have been found in binary systems, where two objects are born together from the same molecular cloud and are gravitationally bound to one another. These binary systems are co-evolving, co-spatial, and have similar compositions, making them crucial to testing and constraining evolutionary models. The widest of these systems (commonly referred to as co-movers), which can have separations up to tens of thousands of AU, are especially important in understanding the evolution of the components because they are far enough away to not be affected by one another. Discovering widely separated brown dwarf systems through their common proper motion is essential in understanding the formation of brown dwarfs by constraining formation theories through their predicted binary fractions. If the primary of the system is a main sequence star, brown dwarfs as companions can benefit from the well-constrained properties of the former, making it possible to infer its age, mass, and other properties which would be otherwise difficult to constrain. Our goal is to identify new widely separated co-moving brown dwarf systems using the CatWISE 2020 catalog, which utilizes enhanced data from the WISE mid-infrared survey mission. Currently, we have identified over 90 candidate co-moving systems comprising a wide variety of primary spectral types including white dwarfs and main sequence stars ranging from A to M, with secondary spectral types ranging from late-type M to late-type T.