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Reference atmosphere for mercury
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Killen, Rosemary M. |
| Copyright Year | 2002 |
| Description | We propose that Ar-40 measured in the lunar atmosphere and that in Mercury's atmosphere is due to current diffusion into connected pore space within the crust. Higher temperatures at Mercury, along with more rapid loss from the atmosphere will lead to a smaller column abundance of argon at Mercury than at the Moon, given the same crustal abundance of potassium. Because the noble gas abundance in the Hermean atmosphere represents current effusion, it is a direct measure of the crustal potassium abundance. Ar-40 in the atmospheres of the planets is a measure of potassium abundance in the interiors, since Ar-40 is a product of radiogenic decay of K-40 by electron capture with the subsequent emission of a 1.46 eV gamma-ray. Although the Ar-40 in the Earth's atmosphere is expected to have accumulated since the late bombardment, Ar-40 in the atmospheres of Mercury and the Moon is eroded quickly by photoionization and electron impact ionization. Thus, the argon content in the exospheres of the Moon and Mercury is representative of current effusion rather than accumulation over the lifetime of the planet. |
| File Size | 113117 |
| Page Count | 3 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20020021914 |
| Archival Resource Key | ark:/13960/t2993606r |
| Language | English |
| Publisher Date | 2002-01-09 |
| Access Restriction | Open |
| Subject Keyword | Lunar And Planetary Science And Exploration Potassium 40 Mercury Atmosphere Lunar Atmosphere Argon Isotopes Reference Atmospheres Regolith Planetary Crusts Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
