IRTF Data Archive Program Information

# # Program information file # PROGRAM_ID 2021B095 PROGRAM_TITLE Constraining the Abundances of n-Butane and 2-Butene in Titan's Atmosphere PROGRAM_INV1 Brendan Steffens PROGRAM_INV2 Conor Nixon PROGRAM_INV3 Tommy Greathouse PROGRAM_INV4 Rohini Giles PROGRAM_INV5 Keeyoon Sung PROGRAM_SCICAT solar system PROGRAM_ABSTRACT_BEG We propose to observe Saturn's moon Titan at wavenumbers 956 cm-1, 965 cm-1, and 1254 cm-1, for the purposes of constraining the abundances of n-butane [n-C4H10] and 2-butene [C4H8] in Titan's stratosphere. These molecules are predicted to be present in detectable abundances at Titan, but in spite of this, neither has been detected to date. The proposed high resolution observations with long integration times will constitute the most ideal dataset obtained yet for investigating these important C4 hydrocarbons at Titan, the abundances and profiles of which are currently poorly constrained. Using the proposed observations, we will be able to detect both n-butane and 2-butene at the 5s confidence level even if their abundances are each as low as 40 parts per billion in the stratosphere. Critical to obtaining those results, we will model the emissions from the v4 band of methane in the 1254 cm-1 observations, allowing the retrieval of a reliable temperature profile which will then be implemented in our modeling of the 956 cm-1 and 966 cm-1 observations. In addition to helping develop our understanding of the formation of Titan's hazes and aerosols, our results will be helpful to future photochemical modeling of Titan's atmosphere, constraining the roles of these two critical components of Titan's C4 chemistry. Our results will also inform NASA's upcoming Dragonfly mission to Titan, as well as developing our understanding of the trace constituents of Titan's hydrocarbon lakes and seas. PROGRAM_ABSTRACT_END