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Report on carbon and nitrogen abundance studies
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Boehm-Vitense, Erika |
| Copyright Year | 1991 |
| Description | The aim of the proposal was to determine the nitrogen to carbon abundance ratios from transition layer lines in stars with different T(sub eff) and luminosities. The equations which give the surface emission line fluxes and the measured ratio of the NV to CIV emission line fluxes are presented and explained. The abundance results are compared with those of photospheric abundance studies for stars in common with the photospheric investigations. The results show that the analyses are at least as accurate as the photospheric determinations. These studies can be extended to F and early G stars for which photospheric abundance determinations for giants are hard to do because molecular bands become too weak. The abundance determination in the context of stellar evolution is addressed. The N/C abundance ratio increases steeply at the point of evolution for which the convection zone reaches deepest. Looking at the evolution of the rotation velocities v sin i, a steep decrease in v sin i is related to the increasing depth of the convection zone. It is concluded that the decrease in v sin i for T(sub eff) less than or approximately = 5800 K is most probably due to the rearrangement of the angular momentum in the stars due to deep convective mixing. It appears that the convection zone is rotating with nearly depth independent angular momentum. Other research results and ongoing projects are discussed. |
| File Size | 2303275 |
| Page Count | 70 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19920002716 |
| Archival Resource Key | ark:/13960/t3324vb12 |
| Language | English |
| Publisher Date | 1991-09-01 |
| Access Restriction | Open |
| Subject Keyword | Astrophysics Stellar Spectra G Stars Stellar Radiation Abundance Stellar Evolution Early Stars Nitrogen Carbon Convection Stellar Luminosity Photosphere Stellar Composition Emission Spectra Spectrum Analysis Angular Momentum Line Spectra F Stars 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 |
