IRTF Data Archive Program Information

# # Program information file # PROGRAM_ID 2022B086 PROGRAM_TITLE Compositional Study and Seasonal Variability of Newly Discovered Comet C/2022 E3 [ZTF]. PROGRAM_INV1 Mohammad Saki PROGRAM_INV2 Erika Gibb PROGRAM_INV3 Ron Vervack PROGRAM_INV4 Michael DiSanti PROGRAM_INV5 Younas Khan PROGRAM_SCICAT comets PROGRAM_ABSTRACT_BEG We propose to use iSHELL at IRTF to study the pre-perihelion, near perihelion, and post-perihelion parent volatile composition in a newly discovered Oort cloud comet [OCC] C/2022 E3 [ZTF]. Because OCCs are among the most primitive objects in the solar system, knowledge of their volatile compositions can improve our understanding of volatile distributions in the protosolar disk. Recent observations have revealed that some comets exhibit variability in parent volatile abundances on long [pre- vs. post-perihelion] and short timescales, particularly for hypervolatiles CO and CH4. Potential mechanisms include seasonal effects, heliocentric distance effects, or nucleus heterogeneity, challenging attempts to develop a taxonomy. Determining whether this variability is rare or common in comets is critical to placing parent volatile composition measurements into the context of solar system formation. We will use three iSHELL settings to obtain abundances [relative to water] of parent volatiles. Lcustom will sample H2O, C2H2, HCN, and NH3. M2 will sample H2O, CO, and OCS. LP1 will sample CH4, C2H6, CH3OH, H2CO and OH prompt emission as a proxy for H2O. The primary goals of this proposal are: [1] Comprehensive compositional study of primitive volatiles, including rarely measured species, [2] Test pre-/post-perihelion asymmetries and short-term variability in outgassing patterns, and [3] Perform a detailed spatial study of H2O to test coma physics models. During the 2022B semester, E3 is available from IRTF primarily during daytime, providing an excellent opportunity to test for compositional variability or asymmetries in a bright OCC. Owing to available high resolving power, large spectral coverage, daytime observing capability, and superior M-band guiding, these studies can only be done with iSHELL at IRTF. PROGRAM_ABSTRACT_END