The Helix Nebula is a low-density, stratified object with near-solar oxygen abundance (8.7), a ~1 dex sulfur deficit, and moderate helium/nitrogen enrichment placing it near the Type I boundary, with abundance variations attributed to ionization structure rather than chemical inhomogeneity.
E., Amayo , A., Arellano-C \'o rdova , K
7 Pith papers cite this work, alongside 61 external citations. Polarity classification is still indexing.
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UNVERDICTED 7representative citing papers
New high-resolution spectra yield abundances for 7 neutron-capture elements in open cluster stars, revealing flat Milky Way gradients for second-peak s- and r-process species and shallower slopes for first-peak s-process.
The paper outlines the goals for the SKA-Mid Galactic Plane survey at 10-15 GHz to deliver the first uniform high-resolution view of ionized structures and feedback in the Milky Way.
A statistical reanalysis of 143 Y_p determinations from 1960s-2022 reveals long-term convergence with change points in the mid-2000s and early 2010s, plus significant non-independence among many extragalactic H II region measurements.
The Galactic Center Lobe is a foreground HII region at ~2 kpc, photoionized and forming a closed outer loop, not a Galactic center feature.
Recalibration of the Hα surface brightness-radius relation with Gaia DR3 parallaxes yields new distances for 1130 planetary nebulae and shows breaks in the Milky Way oxygen radial gradient near the solar radius.
The chapter proposes SKA spectroscopic surveys of the inner and outer Milky Way using OH, CH, radio recombination lines, and H2CO to study molecular cloud formation, ionized gas properties, and CO-dark molecular gas.
citing papers explorer
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SDSS-V LVM: Revealing the Physical and Chemical Structure of the Helix Nebula
The Helix Nebula is a low-density, stratified object with near-solar oxygen abundance (8.7), a ~1 dex sulfur deficit, and moderate helium/nitrogen enrichment placing it near the Type I boundary, with abundance variations attributed to ionization structure rather than chemical inhomogeneity.
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OCCAM X. Neutron Capture Abundances with Keck/HIRES & Magellan/MIKE
New high-resolution spectra yield abundances for 7 neutron-capture elements in open cluster stars, revealing flat Milky Way gradients for second-peak s- and r-process species and shallower slopes for first-peak s-process.
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The 10-15 GHz radio continuum survey of the Galactic Plane with SKAO
The paper outlines the goals for the SKA-Mid Galactic Plane survey at 10-15 GHz to deliver the first uniform high-resolution view of ionized structures and feedback in the Milky Way.
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Fifty years of primordial helium abundances: A statistical reanalysis
A statistical reanalysis of 143 Y_p determinations from 1960s-2022 reveals long-term convergence with change points in the mid-2000s and early 2010s, plus significant non-independence among many extragalactic H II region measurements.
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SDSS-V LVM: Verifying what, and where, the 'Galactic Center' Lobe is
The Galactic Center Lobe is a foreground HII region at ~2 kpc, photoionized and forming a closed outer loop, not a Galactic center feature.
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Recalibration of the H$\alpha$ surface brightness-radius relation for planetary nebulae using Gaia DR3: new distances and the Milky Way oxygen radial gradient
Recalibration of the Hα surface brightness-radius relation with Gaia DR3 parallaxes yields new distances for 1130 planetary nebulae and shows breaks in the Milky Way oxygen radial gradient near the solar radius.
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Spectroscopic surveys with the SKA probing the ionized and molecular Milky Way
The chapter proposes SKA spectroscopic surveys of the inner and outer Milky Way using OH, CH, radio recombination lines, and H2CO to study molecular cloud formation, ionized gas properties, and CO-dark molecular gas.