# # Program information file # PROGRAM_ID 2021B004 PROGRAM_TITLE Confirming new benchmark brown dwarfs with white dwarf companions PROGRAM_INV1 Sarah Casewell PROGRAM_INV2 Adam Schneider PROGRAM_INV3 Jackie Faherty PROGRAM_INV4 Aaron Meisner PROGRAM_INV5 Austin Rothermich PROGRAM_SCICAT stellar PROGRAM_ABSTRACT_BEG We propose to observe 10 newly discovered benchmark brown dwarfs that are wide, common proper motion companions to white dwarfs using Spex on IRTF. All of the targets were discovered through the citizen science programme Backyard Worlds, by searching for moving objects in the solar neighbourhood in images from WISE. A selection of these brown dwarfs were found to have similar motion and distances in the Gaia white dwarf catalogue from DR2. White dwarfs are excellent cosmological clocks and, as these are wide systems, the brown and white dwarf are very unlikely to have ever interacted in a way that would affect the atmosphere of either. The white dwarf will be used to determine the age of the system using cooling tracks, stellar evolutionary models [e.g. MIST] and an initial mass-final mass relation. There are only 6 such systems known to date, and in all but one the brown dwarf is a late-type methane atmosphere T dwarf. Our targets are all cloudy, carbon monoxide rich L dwarfs, thus providing a new set of benchmark systems for these hotter brown dwarfs. Our Spex spectra will be compared to spectral templates, and spectral type related indices calculated in order to then compare these features to those in both forward and spectral retrieval-based models. PROGRAM_ABSTRACT_END