SIMBAD references

2017ApJ...846...24A - Astrophys. J., 846, 24-24 (2017/September-1)

On the iron abundance anomaly in K-dwarf and Hyades stars.


Abstract (from CDS):

Using standard 1D-LTE model atmosphere analysis, we provide an in-depth investigation of iron abundance as derived from neutral and singly ionization iron lines (Fe I, II) in nearby star clusters. Specifically, we replicate the discrepancy regarding Δ[Fe/H], wherein the difference of Fe II-Fe I increases for stars of the same cluster with decreasing Teff, reaching an astonishing 1.0 dex at Teff ∼ 4000 K. Previous studies have investigated this anomaly in the Pleiades and Hyades clusters with no concrete solution. In this analysis, we probe two samples: 63 wide binary field stars where the primary star is of Sun-like temperatures and the secondary is a K-dwarf, ranging from 4231 K <= Teff <= 6453 K, and 33 Hyades stars of temperatures 4268 K <= Teff <= 6072 K. Previous studies have found discrepancies on the order of 1.0 dex. However, we find that these studies have neglected line-blending effects of certain Fe II lines, namely λ = {4508.29 Å, 4993.34 Å, 5197.58 Å, 5325.55 Å, 5425.26 Å, 6456.38 Å}. When these lines are removed from the line-list, we find Δ[Fe/H] decreases to ∼0.6 dex in the field binaries and ∼0.3 dex in the Hyades. The reason for this remaining trend is investigated by probing NLTE effects, as well as age and activity considerations using Ca II H+K emission and Li absorption, but these results appear to be small to negligible.

Abstract Copyright: © 2017. The American Astronomical Society. All rights reserved.

Journal keyword(s): binaries: spectroscopic - open clusters and associations: individual: Hyades - stars: abundances - stars: atmospheres - stars: fundamental parameters - stars: fundamental parameters

Simbad objects: 97

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