Recent work on the line shapes for the spectra of cool stars
Peach, Gillian, Mullamphy, D'arcy F.T., and Whittingham, Ian B. (2007) Recent work on the line shapes for the spectra of cool stars. In: AIP Conference Proceedings: Spectral Lineshapes in Astrophysics (938), pp. 142-147. From: VI Serbian Conference on Spectral Line Shapes in Astrophysics (VI SCSLSA), 11-15 June 2007, Sremski Karlovci, Serbia.
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Accurate pressure broadened profiles of alkali resonance doublets perturbed by helium are needed for modelling of the atmospheres of late M, L and T type brown dwarfs for temperatures up to 3000 K. Previous fully quantum-mechanical calculations of line widths and shifts are extended to consider the line-wing profiles where impact theory is no longer valid. Results are presented for the Lorentzian line widths of the lithium, sodium and potassium resonance lines calculated using both impact and one-perturber theory. Excellent agreement between these two approximations is obtained, demonstrating that quantum-mechanical calculations of the line profiles can be made that are accurate over the whole range of frequencies from the line centre to the line wings.
|Item Type:||Conference Item (Refereed Research Paper - E1)|
|Keywords:||alkali resonance doublets; spectral line breadth; dwarf stars; alkali metals|
|Date Deposited:||06 Jul 2009 00:58|
|FoR Codes:||02 PHYSICAL SCIENCES > 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics > 020201 Atomic and Molecular Physics @ 70%
02 PHYSICAL SCIENCES > 0299 Other Physical Sciences > 029999 Physical Sciences not elsewhere classified @ 30%
|SEO Codes:||97 EXPANDING KNOWLEDGE > 970102 Expanding Knowledge in the Physical Sciences @ 100%|