Physics
Scientific paper
Jul 1996
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1996hst..prop.6760m&link_type=abstract
HST Proposal ID #6760
Physics
Hst Proposal Id #6760 Solar System
Scientific paper
The measured deuterium enrichment in Martian water vapor by afactor of 5.5 relative to the Earth's D/H ratio impliesmassive loss and fractionation of both isotopes in theplanet's history. The current D/H escape ratio is of greatimportance in understanding of these processes. It can beobtained from high- resolution spectroscopy of the D and HLyman-alpha lines. A previous attempt to observe these lineswas made by Bertaux et al. (1992) using GHRS before Cycle 1 inMay 1991 (proposal 2393). It resulted in only an upper limitof 30 R to the D line. We propose to repeat this observationand expect substantial improvements due to (1) anticorrelationof H and D on Mars with solar activity which will provide anincrease of the D line intensity by a factor of 2.2, (2)observation on the limb where the D line is stronger by afactor of 3.5 than at disk center, (3) Mars will be in theantisolar hemisphere, and this will reduce the scattered lightfrom the geocoronal H line by an order of magnitude, (4) ourmeasurement of three parameters of the H profile which makepossible an accurate determination of the D/H escape ratio.The GHRS in ECH-A with LSA should be used on ten orbits. Itis necessary to make this observation in Cycle 6 in January1997 because the next opposition of Mars will be in May 1999when solar activity will be moderate and we will lose theimportant advantage of high H and D densities at solarminimum. Besides, the properties of GHRS are much better forobservations of faint extended
No associations
LandOfFree
The Second Measurement of D/h in Mars' Upper Atmosphere does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The Second Measurement of D/h in Mars' Upper Atmosphere, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Second Measurement of D/h in Mars' Upper Atmosphere will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1118377