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dc.contributor.author | Mashonkina L. | |
dc.date.accessioned | 2018-09-17T21:10:18Z | |
dc.date.available | 2018-09-17T21:10:18Z | |
dc.date.issued | 2000 | |
dc.identifier.issn | 1063-7729 | |
dc.identifier.uri | https://dspace.kpfu.ru/xmlui/handle/net/134620 | |
dc.description.abstract | A method to analyze the statistical equilibrium of the EuII ion based on a 36-level model atom has been developed. The formation of EuII lines without assuming local thermodynamic equilibrium (LTE) is considered for Teff = 5500-7000 K, logg = 4.0, and metallicities [A] from 0 to -1.5. Non-LTE effects in the level populations are primarily due to radiative pumping of excited states from the ground and low-lying levels, which leads to over-population of upper relative to lower levels. As a result, the studied λ4129 and λ6645 Å lines are weaker than in the LTE case. However, due to the small energy differences between even low-lying EuII levels, collisional coupling is strong, and deviations from LTE in EuII lines are modest: for the Sun, non-LTE corrections to the abundance are only 0.04 dex. The non-LTE effects grow with an increase in the effective temperature and with a decrease in the metallicity, so that non-LTE abundance corrections can reach 0.12 dex for Teff = 5500K, logg = 4.0, [A] = -1.5 and 0.1 dex for Teff = 7000K, logg = 4.0, [A] = 0. The effect of inaccuracy in the atomic parameters for EuII on the non-LTE calculations is examined. Analysis of the profiles of the solar EuII λ4129 and λ6645 Å lines is used to empirically refine estimates of the efficiency of collisional processes in forbidden transitions in establishing the distribution of EuII ions over excited states. © 2000 MAIK "Nauka/Interperiodica". | |
dc.relation.ispartofseries | Astronomy Reports | |
dc.title | Non-LTE analysis of the formation of EuII lines in the atmospheres of solar-type stars | |
dc.type | Article | |
dc.relation.ispartofseries-issue | 8 | |
dc.relation.ispartofseries-volume | 44 | |
dc.collection | Публикации сотрудников КФУ | |
dc.relation.startpage | 558 | |
dc.source.id | SCOPUS10637729-2000-44-8-SID0034336688 |