# # Program information file # PROGRAM_ID 2023A030 PROGRAM_TITLE Confirming new benchmark brown dwarfs in binaries with white dwarfs PROGRAM_INV1 Jenni French PROGRAM_INV2 Sarah Casewell PROGRAM_INV3 Adam Schneider PROGRAM_INV4 Beth Henderson PROGRAM_INV5 Jackie Faherty PROGRAM_SCICAT stellar PROGRAM_ABSTRACT_BEG We propose to observe 6 newly discovered benchmark brown dwarfs which are wide, common proper motion companions to white dwarfs using SpeX on IRTF. These targets have been identified via the citizen science project Backyard worlds by searching for co-moving objects to known Gaia white dwarfs in WISE. In these wide white dwarf-brown dwarf binaries, it is unlikely that the brown dwarf was significantly affected by the death of the white dwarf progenitor, meaning that the brown dwarf evolution and atmosphere is the same as a lone brown dwarf. Currently, only 6 of these systems are known and 5 of those host late T dwarfs. Our targets are cloudy L dwarfs that are CO rich, and will provide a new set of benchmark systems for earlier-type, hotter brown dwarfs. Our proposed observations use the SpeX spectrograph in prism mode with the 0.8' slit, which will cover the 0.8-2.5um wavelength range, a setup that is often used to observe substellar objects. We will then confirm the substellar nature of the targets and determine the spectral type of the L dwarfs by comparing them to brown dwarf spectral templates and calculating spectral type related indices. PROGRAM_ABSTRACT_END