%0 Journal Article
%T Red Supergiant Stars as Cosmic Abundance Probes: II. NLTE Effects in J-band Silicon Lines
%+ Laboratoire Univers et Particules de Montpellier (LUPM)
%A Bergemann, Maria
%A Kudritzki, Rolf-Peter
%A Wueurl, Matthias
%A Plez, Bertrand
%A Davies, Ben
%A Gazak, Zach
%Z 17 pages, accepted for publication in ApJ
%< avec comité de lecture
%Z LUPM:12-063
%@ 2041-8205
%J The Astrophysical journal letters
%I Bristol : IOP Publishing
%V 764
%N 2
%P 115
%8 2013-02-01
%D 2013
%Z 1212.2649
%Z 2013ApJ...764..115B
%R 10.1088/0004-637X/764/2/115
%Z Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR]
%Z Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR]Journal articles
%X Medium resolution J-band spectroscopy of individual red supergiant stars is a promising tool to investigate the chemical composition of the young stellar population in star forming galaxies. As a continuation of recent work on iron and titanium, detailed non-LTE calculations are presented to investigate the influence of NLTE on the formation of silicon lines in the J-band spectra of red supergiants. Substantial effects are found resulting in significantly stronger absorption lines of neutral silicon in non-LTE. As a consequence, silicon abundances determined in non-LTE are significantly smaller than in LTE with the non-LTE abundance corrections varying smoothly between -0.4 dex to -0.1 dex for effective temperatures between 3400K to 4400K. The effects are largest at low metallicity. The physical reasons behind the non-LTE effects and the consequences for extragalactic J-band abundance studies are discussed.
%G English
%L hal-00785787
%U https://hal.science/hal-00785787
%~ IN2P3
%~ CNRS
%~ UNIV-MONTP2
%~ LUPM
%~ MIPS
%~ UNIV-MONTPELLIER
%~ LUPM_AS
%~ UM1-UM2