Meteor showers on the lunar atmosphere

To investigate the role of impacts as a source of gas in the Moon's atmosph ere, we review a series of observations of the lunar limb made during inter action with the Leonids (1995 and 1997), Quadrantids (1999) and Geminids (1 999). Using Chamberlain's model for the exosphere, with an appropriately ad justed partition function, we calculated the scale height (and thus the kin ematic temperature) and the emission of the Na atmosphere, and compared the results with observations published in the literature. We found evidence o f small enhancements of temperature and emission of Na during the 1995 and 1997 Leonids, while no enhancements were detected during the 1999 Quadranti ds and Geminids. Possible explanations of the different behaviour are prese nted.