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C-h hot bands in the near-ir emission spectra of leonids
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Holm, R. Scoville, J. Freund, F. T. Seelemann, R. Freund, M. M. |
| Copyright Year | 2002 |
| Description | The reported infrared (IR) emission spectra from 1999 Leonid fireballs show a 3.4 micron C-H emission band and unidentified bands at longer wavelengths. Upon atmospheric entry, the Leonid meteorites were flash-heated to temperatures around 2400K, which would destroy any organics on the surface of the meteorite grains. We propose that the nu(sub )CH emission band in the Leonid emission spectra arises from matrix-embedded C(sub n)-H-O entities that are protected from instant pyrolysis. Our model is based on IR absorption nu(sub )CH bands, which we observed in laboratory-grown MgO and natural olivine single crystals, where they arise from C(sub n)-H-O units imbedded in the mineral matrix, indicative of aliphatic -CH2- and -CH3 organics. Instead of being pyrolyzed, the C(sub n)-H-O entities in the Leonid trails become vibrationally excited to higher levels n = 1, 2, 3 etc. During de-excitation they emit at 3.4 microns, due to the (0 => 1) transition, and at longer wavelengths, due to hot bands. As a first step toward verifying this hypothesis we measured the C-H vibrational manifold of hexane (C6H14). The calculated positions of the (2 => l ) , (3 => 2), and possibly (4 => 3) hot bands agree with the Leonid emission bands at 3.5, 3.8 and 4.l microns. |
| File Size | 223955 |
| Page Count | 4 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20030058899 |
| Archival Resource Key | ark:/13960/t0tr0vn0p |
| Language | English |
| Publisher Date | 2002-11-01 |
| Access Restriction | Open |
| Subject Keyword | Astronomy Near Infrared Radiation Olivine Pyrolysis Emission Spectra Spectral Bands Magnesium Oxides Infrared Absorption Infrared Spectra Leonid Meteoroids Atmospheric Entry Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
