IRTF Data Archive Program Information

# # Program information file # PROGRAM_ID 2021A004 PROGRAM_TITLE VNIR Spectral Properties of the G-Class Asteroids: Implications for Surface Mineralogy and Geologic Evolution. PROGRAM_INV1 Justin Germann PROGRAM_INV2 Sherry Fieber-Beyer PROGRAM_INV3 PROGRAM_INV4 PROGRAM_INV5 PROGRAM_SCICAT solar system PROGRAM_ABSTRACT_BEG This study will utilize the NASA IRTF SpeX instrument to obtain near-infrared spectra of five targets covering the ~0.70--2.52 um spectral interval. We seek to answer two research questions: what VNIR spectral features are common among G-class asteroids, and what implications do the observed mineralogy have for an asteroid's geologic history? In particular, we will be looking for spectral evidence supporting the presence of ammoniated phyllosilicates and non-ammoniated phyllosilicates. Spectrally, ammoniated phyllosilicate features would include the lack of a 0.7 um feature [Vilas & Sykes 1996], and the presence of weak 1.56-, 2.05-, and 2.12-um absorption features [Ferrari et al. 2019]. Spectral evidence supporting the presence of non-ammoniated phyllosilicates would be the presence of 0.7-, 0.95-, 1.4-, 2.3- and 2.45-um absorption features [De Angelis et al. 2016; Vilas & Sykes 1996]. The phyllosilicates type can be indicative of metamorphic events. For example, if a surface which has produced secondary minerals via aqueous alteration were to be heated > 400degreesC, these secondary minerals [brucite, serpentine] would metamorphose at 300<=T<=600 degreesC [Ostrowski et al. 2010], and ammoniated phyllosilicates could form. However, the presence of non-ammoniated phyllosilicates would indicate that the asteroid has not been heated >300 degreesC, resulting in the preservation of ammonia rich organics and non-ammoniated phyllosilicates, and would indicate a primitive surface mineralogy PROGRAM_ABSTRACT_END