IRTF Data Archive Program Information

# # Program information file # PROGRAM_ID 2021B082 PROGRAM_TITLE Ammoniated Salts and Primary Volatiles in comet C/2021 A1 Leonard: a unique opportunity PROGRAM_INV1 Michael Mumma PROGRAM_INV2 Sara Faggi PROGRAM_INV3 Geronimo Villanueva PROGRAM_INV4 PROGRAM_INV5 PROGRAM_SCICAT solar system PROGRAM_ABSTRACT_BEG We propose to investigate primary volatiles and ammoniated salts in comet C/2021 A1 [Leonard] as it approaches perihelion. Ammoniated salts can be produced at 10-15 K and they will survive until ~200K and higher, meaning that salts now present in cometary nuclei could have formed in the natal interstellar cloud core. Once ejected by a comet, especially at very small Rh, salts can be heated to dissociation temperatures by solar radiation and dissociate into their constituent species [HCN, NH3...]. Comet A1 is an excellent target for this investigation, with observations proposed near 1 au and near perihelion [0.6 au]. To obtain a complete characterization of the outgassing activity and composition in identifying the possible presence of ammonium salts we propose to follow the object as closely as possible during its perihelion approach on three 2-day visits. The geocentric Doppler shift is quite large on all three dates, greatly displacing the CO and CH4 cometary lines from their telluric counterparts and permitting their detection. On each 2-day visit, the first day will target the nitrile region and especially HCN, NH3, NH2 and H2O, [2.9 to 3.1 um] in L1 and the carbon-stretch region [3.3 to 3.5 um] in Lp1 [targeting CH4, C2H6, CH3OH, and OH*] while the second day will target both the nitrile region in L1 and CO, CN, OCS and H2O in M1. We will target HDO in a custom setting, Lp1-c. In doing so, we will characterize the comet's chemical composition and test the origin of its material. PROGRAM_ABSTRACT_END