Roman Space Telescope Ultracool Dwarf Colors

The Nancy Grace Roman Space Telescope, planned to launch in Fall 2026 and begin survey operations in early 2027, is anticipated to discover thousands of ultracool dwarfs with its exceptional field of view and infrared photometric depth. Compared to other stellar and extragalactic objects, ultracool dwarfs are relatively rare and require specific selection methods to be confidently identified. Color-color cuts are one of the most effective of such selection techniques and applying color-spectral type relations afterwards is a critical step in confirming candidates as ultracool dwarfs. Using both color-color selection and color-spectral type relations will be advantageous to separate the extragalactic and ultracool dwarf “little red dots” that are prevalent in recent deep extragalactic fields. We present color-spectral type relations for field, young, and low metallicity/subdwarf ultracool dwarfs based on recent discoveries from the Backyard Worlds Collaboration and using the Simple Archive. The polynomial fits to the color-spectral type relations will allow for the characterization of ultracool dwarf candidates beyond color-color selection and enable calculations such as photometric distances. With the expected volume of Roman discoveries, tools like color-spectral type relations will help increase candidate evaluation efficiency.