Chemical Evolution of the Galactic Bulge as Derived from High-Resolution Infrared Spectroscopy of K and M Red Giants [PDF]
, 2006 We present chemical abundances in K and M red-giant members of the Galactic bulge derived from high-resolution infrared spectra obtained with the Phoenix spectrograph on Gemini-South.
Bessel M. S. +10 more
core +3 more sources
Analysis of chemical abundances in planetary nebulae with [WC] central stars [PDF]
Astronomy & Astrophysics, 2013 Accepted for publication in A&A. 15 Tables and 18 Figures.
Maria Teresa Ruiz +7 more
openaire +5 more sources
Chemical abundances in Seyfert galaxies – X. Sulphur abundance estimates
Monthly Notices of the Royal Astronomical Society, 2023 ABSTRACT For the first time, the sulphur abundance relative to hydrogen (S/H) in the narrow-line regions of a sample of Seyfert 2 nuclei (Sy 2s) has been derived via direct estimation of the electron temperature. Narrow emission-line intensities from the Sloan Digital Sky Survey (SDSS) Data Release 17 (DR17) [in the wavelength range 3000
Oli L Dors +14 more
openaire +3 more sources
Li-rich Giants Identified from LAMOST DR8 Low-resolution Survey
The Astronomical Journal, 2023 A small fraction of giants possess photospheric lithium (Li) abundance higher than the value predicted by the standard stellar evolution models, and the detailed mechanisms of Li enhancement are complicated and lack a definite conclusion.
Beichen Cai +5 more
doaj +1 more source
Search for Extremely Metal-poor Stars with Gemini-N/Graces. I. Chemical-abundance Analysis
The Astrophysical Journal, 2023 We present stellar parameters and abundances of 13 elements for 18 very metal-poor (VMP; [Fe/H] < –2.0) stars, selected as extremely metal-poor (EMP; [Fe/H] < –3.0) candidates from the Sloan Digital Sky Survey and Large sky Area Multi-Object Fiber ...
Miji Jeong +7 more
doaj +1 more source
How Efficient is Rotational Mixing in Massive Stars ? [PDF]
, 2007 The VLT-Flames Survey for Massive Stars (Evans05,Evans06) provides recise measurements of rotational velocities and nitrogen surface abundances of massive stars in the Magellanic Clouds.
Anders, P. +3 more
core +6 more sources
High-resolution Chemical Abundances of the Nyx Stream
The Astrophysical Journal, 2023 Nyx is a nearby, prograde, and high-eccentricity stellar stream physically contained in the thick disk, but its origin is unknown. Nyx could be the remnant of a disrupted dwarf galaxy, in which case the associated dark matter substructure could affect ...
Shuyu Wang +7 more
doaj +1 more source
Evidence for Ubiquitous Carbon Grain Destruction in Hot Protostellar Envelopes
The Astrophysical Journal Letters, 2023 Earth is deficient in carbon and nitrogen by up to ∼4 orders of magnitude compared with the Sun. Destruction of (carbon- and nitrogen-rich) refractory organics in the high-temperature planet-forming regions could explain this deficiency.
Pooneh Nazari +4 more
doaj +1 more source
Neon and Sulfur Abundances of Planetary Nebulae in the Magellanic Clouds [PDF]
, 2007 The chemical abundances of neon and sulfur for 25 planetary nebulae (PNe) in the Magellanic Clouds are presented. These abundances have been derived using mainly infrared data from the Spitzer Space Telescope.
Aller L. H. +12 more
core +4 more sources
Connecting the primordial and Galactic deuterium abundances [PDF]
, 2007 The deuterium abundances inferred from observations of the interstellar medium within 1-2 kpc of the Sun range over a factor of three and the corresponding oxygen abundances show an even larger dispersion.
Romano, Donatella +2 more
core +3 more sources