The photospheric barium spectrum: Solar abundance and collision broadening of Baiilines by hydrogen

✍ Scribed by Hartmut Holweger; Edith A. Müller

• Publisher: Springer
• Year: 1974
• Tongue: English
• Weight: 584 KB
• Volume: 39
• Category: Article
• ISSN: 0038-0938
• DOI: 10.1007/bf00154968

✦ Synopsis

A study of the solar Ba It spectrum leads to a solar abundance of barium of logeBn = --2.11 +0.12, on the scale loge~-12. The observed asymmetry of the resonance line ,,t4554 is consistent with an isotopic abundance ratio equal to the terrestrial one. The meteoritic Ba/Si abundance ratio found in carbonaceous chondrites appears to exceed the solar ratio by 0.1 to 0.2 dex (Section 5).

The broadening by collisions with hydrogen atoms is determined from the solar spectrum (Section 4). Damping half-widths, 7H, of the three stronger Ba H lines turn out to be larger by a factor of about 3.0 than predicted from pure van der Waals interaction of dipoles.

Departuresfi'om LTE appear to be present in the cores of the resonance lines and of the lines arising from the metastable 5D levels (Section 6). The equivalent widths, however, remain practically unaffected.

Equivalent widths of neutral barium lines are predicted and some new identifications of photospheric Ba i lines are suggested (Section 7).