Publication Date:
2014-12-24
Description:
Publication date: Available online 23 December 2014 Source: Planetary and Space Science Author(s): Smitha V. Thampi , R. Sridharan , Tirtha Pratim Das , S.M. Ahmed , J.A. Kamalakar , Anil Bhardwaj The measurements carried out by the Chandra's Altitudinal Composition Explorer (CHACE) onboard the Moon Impact Probe (MIP) of Chandrayaan I mission is used to obtain information on the 2-D distribution of the lunar atmospheric H 2 by a novel approach that makes use of the basic fact that the Moon has a Surface Boundary Exosphere (SBE).These are the ‘first’ daytime in situ measurements of lunar H 2 covering the 20°S to 88°S latitude region centered ~14°E longitude. A critical examination of the observed spatial features of the surface number density of H 2 vis-à-vis the surface topography delineated from the Lunar Laser Ranging Instrument (LLRI) in the main orbiter Chandrayaan –I, indicates that that lunar surface process may be important in introducing small scale variations in the H 2 number density. Another constituent which exhibited spatial variation in the observed partial pressure is 40 Ar and it was hypothesized that it is indicative of the spatial heterogeneity in the radiogenic activity of the Lunar interior ( Sridharan et al., 2013a ). The absolute number density at the surface and also the latitude/altitude variation of the densities that are reported for the first time, highlight the complexities of the sunlit lunar atmosphere.
Print ISSN:
0032-0633
Electronic ISSN:
1873-5088
Topics:
Geosciences
,
Physics
