2004c) Search for the OH (X2P) Meinel band emission in meteors as a tracer of mineral water in comets: Detection of N21(A-X

We report the discovery of the N21 A-X Meinel band in the 780–840 nm meteor emission from two Leonid meteoroids that were ejected less than 1,000 years ago by comet 55P/Tempel-Tut-tle. Our analysis indicates that the N21 molecule is at least an order of magnitude less abun-dant than expected, possibly as a result of charge transfer reactions with meteoric metal atoms. This new band was found while searching for rovibrational transitions in the X2P electronic ground state of OH (the OH Meinel band), a potential tracer of water bound to minerals in cometary matter. The electronic A-X transition of OH has been identified in other Leonid me-teors. We did not detect this OH Meinel band, which implies that the excited A state is not populated by thermal excitation but by a mechanism that directly produces OH in low vi-brational levels of the excited A2S state. Ultraviolet dissociation of atmospheric or meteoric water vapor is such a mechanism, as is the possible combustion of meteoric organics. Key Words: Prebiotic molecules—Origin of life—Meteors—Molecular band emission. Astrobiol-ogy 4, 109–121. 10