IRTF Data Archive Program Information

# # Program information file # PROGRAM_ID 2022B028 PROGRAM_TITLE Investigating the origin of Nereid and the spectral hints of NH4-bearing minerals on its surface PROGRAM_INV1 Richard Cartwright PROGRAM_INV2 Bryan Holler PROGRAM_INV3 Michael Lucas PROGRAM_INV4 Ben Sharkey PROGRAM_INV5 Driss Takir PROGRAM_SCICAT major planets / satellites PROGRAM_ABSTRACT_BEG We propose to use SpeX to characterize the surface composition of the Neptunian moon Nereid, which could represent a key compositional link between ice giant satellites and trans-Neptunian Objects [TNO]. The available spectra of Nereid suggest that it has a low albedo surface with weak H2O bands and spectral hints of absorption bands between 2 and 2.3 microns that could result from NH4-bearing minerals, similar to absorption bands detected on the classical Uranian moons and H2O-bearing TNOs like Charon and Orcus. However, the low signal-to-noise [S/N] of these data limits our ability to constrain the composition of Nereid and interpret the possible compositional links between this Neptunian moon and different populations of icy bodies in the outer Solar System. Therefore, we aim to collect higher S/N, near-infrared spectra of Nereid to investigate its surface composition. The PRISM mode of SpeX [R ~94, 0.8'' slit] is ideal for the characterization of possible NH4-bearing minerals with spectral features in K band. The previously detected 2.04-micron and 2.2-micron bands are relatively wide, spanning ~0.05 microns and ~0.07 microns, respectively, requiring R of > 40 to detect. We request time to observe Nereid on two different nights. The resulting spectra will be combined with existing PRISM spectra of Nereid into a grand average spectrum with lower point-to-point variation [S/N ~20]. We will guide using MORIS [0.7'' dichroic] to help reduce flux loss along the slit. PROGRAM_ABSTRACT_END