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Analysis of iue observations of hydrogen in comets
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Combi, Michael R. Feldman, Paul D. |
| Copyright Year | 1993 |
| Description | The large body of hydrogen Lyman-alpha observations of cometary comae obtained with the International Ultraviolet Explorer satellite has gone generally unanalyzed because of two main modeling complications. First, the inner comae of many bright (gas productive) comets are often optically thick to solar Lyman-alpha radiation. Second, even in the case of a small comet (low gas production) the large IUE aperture is quite small as compared with the immense size of the hydrogen coma, so an accurate model which properly accounts for the spatial distribution of the coma is required to invert the inferred brightnesses to column densities and finally to H atom production rates. Our Monte Carlo particle trajectory model (MPTM), which for the first time provides the realistic full phase space distribution of H atoms throughout the coma was used as the basis for the analysis of IUE observations of the inner coma. The MCPTM includes the effects of the vectorial ejection of the H atoms upon dissociation of their parent species (H2O and OH) and of their partial collisional thermalization. Both of these effects are crucial to characterize the velocity distribution of the H atoms. A new spherical radiative transfer calculation based on our MCPTM was developed to analyze IUE observations of optically thick H comae. The models were applied to observations of comets P/Giacobini-Zinner and P/Halley. |
| File Size | 1475515 |
| Page Count | 23 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19930014042 |
| Archival Resource Key | ark:/13960/t1gj4dn0x |
| Language | English |
| Publisher Date | 1993-03-01 |
| Access Restriction | Open |
| Subject Keyword | Astrophysics Cometary Atmospheres Lyman Alpha Radiation Spatial Distribution Giacobini-zinner Comet Hydrogen Spaceborne Astronomy Ultraviolet Spectra Iue Radiative Transfer Dissociation Halley's Comet Monte Carlo Method 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 |
