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

Despite its importance for understanding the nature of early stellargenerations and for constraining Galactic bulge formation models, at presentlittle is known about the metal-poor stellar content of the central Milky Way.This is a consequence of the great distances involved and intervening dustobscuration, which challenge optical studies. However, the Apache PointObservatory Galactic Evolution Experiment (APOGEE), a wide-area, multifiber,high-resolution spectroscopic survey within Sloan Digital Sky Survey III(SDSS-III), is exploring the chemistry of all Galactic stellar populations atinfrared wavelengths, with particular emphasis on the disk and the bulge. Anautomated spectral analysis of data on 2,403 giant stars in twelve fields inthe bulge obtained during APOGEE commissioning yielded five stars with lowmetallicity([Fe/H]$\le-1.7$), including two that are very metal-poor[Fe/H]$\sim-2.1$ by bulge standards.  Luminosity-based distance estimates place the five stars within the outerbulge, where other 1,246 of the analyzed stars may reside. A manual reanalysisof the spectra verifies the low metallicities, and finds these stars to beenhanced in the $\alpha$-elements O, Mg, and Si without significant$\alpha$-pattern differences with other local halo or metal-weak thick-diskstars of similar metallicity, or even with other more metal-rich bulge stars.While neither the kinematics nor chemistry of these stars can yet definitivelydetermine which, if any, are truly bulge members, rather than denizens of otherpopulations co-located with the bulge, the newly-identified stars reveal thatthe chemistry of metal-poor stars in the central Galaxy resembles that ofmetal-weak thick-disk stars at similar metallicity.

Very Metal-poor Stars in the Outer Galactic Bulge Found by the Apogee Survey