English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We report the detection of an Al II line at 2669.155 Angstroms in 11metal-poor stars, using ultraviolet spectra obtained with the Space TelescopeImaging Spectrograph on board the Hubble Space Telescope. We derive Alabundances from this line using a standard abundance analysis, assuming localthermodynamic equilibrium (LTE). The mean [Al/Fe] ratio is -0.06 +/- 0.04(sigma = 0.22) for these 11 stars spanning -3.9 < [Fe/H] < -1.3, or [Al/Fe] =-0.10 +/- 0.04 (sigma = 0.18) for 9 stars spanning -3.0 < [Fe/H] < -1.3 if twocarbon-enhanced stars are excluded. We use these abundances to perform anempirical test of non-LTE (NLTE) abundance corrections predicted for resonancelines of Al I, including the commonly-used optical Al I line at 3961 Angstroms.The Al II line is formed in LTE, and the abundance derived from this linematches that derived from high-excitation Al I lines predicted to have minimalNLTE corrections. The differences between the abundance derived from the Al IIline and the LTE abundance derived from Al I resonance lines are +0.4 to +0.9dex, which match the predicted NLTE corrections for the Al I resonance lines.We conclude that the NLTE abundance calculations are approximately correct andshould be applied to LTE abundances derived from Al I lines.

Detection of Al II in the Ultraviolet Spectra of Metal-Poor Stars: An Empirical LTE Test of NLTE Aluminum Abundance Calculations