# # Program information file # PROGRAM_ID 2021A078 PROGRAM_TITLE Confirmation and Mapping of Phosphine on Venus PROGRAM_INV1 Clara Sousa-Silva PROGRAM_INV2 Jason Dittmann PROGRAM_INV3 Therese Encrenaz PROGRAM_INV4 Thomas Greathouse PROGRAM_INV5 Pedro Machado PROGRAM_SCICAT solar system PROGRAM_ABSTRACT_BEG We have a tentative detection of phosphine gas in the atmosphere of Venus through independent observations, collected by both JCMT and ALMA, of the J=1-0 transition at microwave frequencies. These observations suggest a phosphine abundance between 5 and 20 parts-per-billion in the cloud deck of Venus. The presence of this gas is highly unexpected as phosphine is very quickly destroyed in the Venusian atmosphere, and all known abiotic production mechanisms cannot explain these phosphine concentrations. However, other possible contaminants, such as sulfur dioxide, offer potential alternate explanations for the observed feature observed in the JCMT and ALMA data. Additionally, recent re-examination of archival data [from Pioneer-Venus LNMS and TEXES] provides conflicting information on the presence of phosphine in the clouds. It is therefore crucial to investigate the presence of phosphine on Venus, and its spacial and temporal variation, to develop a better understanding of the Venusian atmosphere. We propose to use TEXES's unique high-spectral resolution infrared capabilities to unambiguously detect and map phosphine on Venus at previously unobserved wavelengths. We request 4 hours of daytime observations, spread across 3 days, to achieve the following objectives: 1] To unambiguously confirm the presence of phosphine by detecting multiple strong features in the infrared [between 1115 and 1211 wavenumbers]. 2] To geographically map the presence of phosphine across longitude and latitude, and investigate its spacial and temporal variability, using TEXES capability to spatially map the entire disk of Venus. PROGRAM_ABSTRACT_END