Kavli Affiliate: Feng Wang
| First 5 Authors: Sofya Alexeeva, Yu Wang, Gang Zhao, Feng Wang, Yong Wu
| Summary:
The non-local thermodynamical equilibrium (NLTE) line formation of Y I and Y
II is considered in 1D LTE model atmospheres of F-G-K-type stars. The model
atom was constructed with the most up-to-date atomic data, including quantum
cross sections and rate coefficients for transitions in inelastic collisions of
Y I and Y II with hydrogen atoms. For seven reference stars, we obtained an
agreement between NLTE abundances inferred from the two ionization stages,
while the difference in LTE abundance (Y I – Y II) can reach up to -0.31 dex.
In the atmospheres of F-G-K-type stars, for both Y I and Y II lines, the NLTE
abundance corrections are positive. In solar metallicity stars, the NLTE
abundance corrections for Y II lines do not exceed 0.12 dex, while in
atmospheres of metal-poor stars they do not exceed 0.21 dex. For Y I lines, the
NLTE abundance corrections can reach up to 0.5 dex. We determined the yttrium
NLTE abundances for a sample of 65 F and G dwarfs and subgiants in the
-2.62~$leq$~[Fe/H]~$leq$~+0.24 metallicity range, using high-resolution
spectra. For stars with [Fe/H]~$leq$~-1.5, [Y/Fe] versus [Fe/H] diagram
reveals positive trend with an average value of [Y/Fe]~$simeq$~0. For
metal-poor stars, among Sr, Y, and Zr, the arrangement [Sr/Fe] < [Y/Fe] <
[Zr/Fe] remains consistent. The current study is useful for the Galactic
chemical evolution research. The model atom will be applied for NLTE yttrium
abundance determination in very metal-poor stars studied with LAMOST and
Subaru.
| Search Query: ArXiv Query: search_query=au:”Feng Wang”&id_list=&start=0&max_results=3