IBEX-Lo Observations of Energetic Neutral Hydrogen Atoms Originating from the Lunar Surface
Coimbra, Joao Carlos; Pinto, Iraja Damiani; Wurdig, Norma Luiza; Do Carmo, Dermeval Aparecido
Planetary and Space Science 60(1): 297-303
2012
ISSN/ISBN: 0032-0633 DOI: 10.1016/j.pss.2011.09.009
Accession: 036225390
In this paper we present quantitative results of observations of energetic neutral atoms (ENAs) originating from the lunar surface. These ENAs, which are hydrogen atoms, are the result of the solar wind protons being reflected from and neutralised at the surface of the Moon. These measurements were made with IBEX-Lo on NASA s IBEX satellite. From these measurements we derive the energy spectrum of the ENAs, their flux, and the lunar albedo for ENAs (i.e., the ratio of ENAs to the incoming solar wind protons). The energy spectra of the ENAs clearly show that their origin is directly from the solar wind via backscattering, and that they are not sputtered atoms. From several observation periods we derived an average global albedo ofAH=.9 .5. From the observed energy spectra we derive a generic spectrum for unshielded bodies in the solar wind.