首页    期刊浏览 2024年10月06日 星期日
登录注册

文章基本信息

  • 标题:The EUV spectrum of the Sun: Quiet- and active-Sun irradiances and chemical composition ⋆
  • 本地全文:下载
  • 作者:G. Del Zanna
  • 期刊名称:Astronomy & Astrophysics
  • 印刷版ISSN:0004-6361
  • 电子版ISSN:1432-0746
  • 出版年度:2019
  • 卷号:624
  • DOI:10.1051/0004-6361/201834842
  • 语种:English
  • 出版社:EDP Sciences
  • 摘要:We benchmark new atomic data against a selection of irradiances obtained from medium-resolution quiet-Sun spectra in the extreme ultraviolet (EUV), from 60 to 1040 Å. We used as a baseline the irradiances measured during solar minimum on 2008 April 14 by the prototype (PEVE) of the Solar Dynamics Observatory Extreme ultraviolet Variability Experiment (EVE). We took into account some inconsistencies in the PEVE data, using flight EVE data and irradiances we obtained from Solar and Heliospheric Observatory (SoHO) Coronal Diagnostics Spectrometer (CDS) data. We performed a differential emission measure and find overall excellent agreement (to within the accuracy of the observations, about 20%) between predicted and measured irradiances in most cases, although we point out several problems with the currently available ion charge-state distributions. We used the photospheric chemical abundances of Asplund et al. (2009, ARA&A, 47, 481). The new atomic data are nearly complete in this spectral range for medium-resolution irradiance spectra. Finally, we used observations of the active Sun in 1969 to show that the composition of the solar corona up to 1 MK is nearly photospheric in this case as well. Variations of a factor of 2 are present for higher-temperature plasma, which is emitted within active regions. These results are in excellent agreement with our previous findings.
  • 关键词:enSun: abundancesSun: coronaSun: UV radiationline: identificationtechniques: spectroscopic
国家哲学社会科学文献中心版权所有