# # Program information file # PROGRAM_ID 2023A050 PROGRAM_TITLE Infrared Search for Undetected C4 Hydrocarbons in Titan's Atmosphere PROGRAM_INV1 Conor Nixon PROGRAM_INV2 Brendan Steffens PROGRAM_INV3 Thomas Greathouse PROGRAM_INV4 Rohini Giles PROGRAM_INV5 Keeyoon Sung PROGRAM_SCICAT major planets / satellites PROGRAM_ABSTRACT_BEG We propose to observe Titan, the largest moon of Saturn, at wavenumbers 910 cm-1, 976 cm-1 and 1257 cm-1, for the purposes of constraining abundances of multiple C4 hydrocarbons in Titan's stratosphere, these being the following: cis-2-butene [cis-2-C4H8], 1-butene [1-C4H8], and 1,3-butadiene [1,3-C4H6]. Photochemical models of Titan's atmosphere consistently predict the presence of these molecules, but none of them has been detected, thus far. Long integration times with the proposed observations will facilitate detection of these elusive molecules, the abundances and profiles of which are currently only very poorly constrained. A critical component of our search will be the observations on the 1257 cm-1 setting, which will allow us to retrieve a reliable and concurrent temperature profile which will then be implemented in our modeling of the 910 cm-1 and 976 cm-1 observations. In addition to developing our understanding of the formation of Titan's aerosols and hazes, the results from modeling these observations will be helpful in the future photochemical modeling of Titan's atmosphere, constraining the roles of these critical components of Titan's C4 chemistry. Additionally, our results will provide useful information for the upcoming NASA Dragonfly mission to Titan, as well as contributing to our understanding of the trace constituent molecules in Titan's hydrocarbon lakes and seas. PROGRAM_ABSTRACT_END