Results 51 to 60 of about 4,406,721 (399)
Chemical Abundances of Hydrostatic and Explosive Alpha-elements in Sagittarius Stream Stars [PDF]
, 2018 We analyze chemical abundances of stars in the Sagittarius (Sgr) tidal stream using high-resolution Gemini+GRACES spectra of 42 members of the highest surface-brightness portions of both the trailing and leading arms.
J. Carlin +3 more
semanticscholar +1 more source
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
Interstellar Extinction and Elemental Abundances [PDF]
, 2020 Elements in the interstellar medium (ISM) exist in the form of gas or dust. The interstellar extinction and elemental abundances provide crucial constraints on the composition, size and quantity of interstellar dust. Most of the extinction modeling efforts have assumed the total abundances (both in gas and in dust) of the dust-forming elements---known ...
arxiv +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
A volume-limited survey of mCP stars within 100 pc – I. Fundamental parameters and chemical abundances [PDF]
Monthly notices of the Royal Astronomical Society, 2018 We present the first results of a volume-limited survey of main sequence (MS) magnetic chemically peculiar (mCP) stars. The sample consists of all identified intermediate-mass MS stars (mCP and non-mCP) within a heliocentric distance of $100\,{\rm pc ...
J. Sikora +5 more
semanticscholar +1 more source
Rotation and chemical abundances of Ap/Bp stars in the open cluster NGC 6475 [PDF]
Mon.Not.Roy.Astron.Soc.376:361-370,2007, 2006 The connection between age, rotation and chemical abundance of magnetic Ap stars is poorly understood. Using open clusters, we are able to study samples of stars that are both co-eval and co-environmental. By determining rotation and chemical abundance for Ap star members of clusters with various ages, the variations of these properties as a function ...
arxiv +1 more source
Chemical Abundances in the Leading Arm of the Magellanic Stream [PDF]
, 2018 The Leading Arm (LA) of the Magellanic Stream is a vast debris field of H i clouds connecting the Milky Way and the Magellanic Clouds. It represents an example of active gas accretion onto the Galaxy.
A. Fox +11 more
semanticscholar +1 more source
Cumulative Oxygen Abundances of Spiral Galaxies [PDF]
2012, ApJ, 750, 167, 2012 Studying the global evolution of spiral galaxies requires determining their overall chemical compositions. However, since spirals tend to possess gradients in their chemical compositions, determining their overall chemical abundances poses a challenge. In this study, the framework for a newly proposed method for determining the overall oxygen abundance
arxiv +1 more source
TOPoS. IV. Chemical abundances from high-resolution observations of seven extremely metal-poor stars [PDF]
, 2018 Context. Extremely metal-poor (EMP) stars provide us with indirect information on the first generations of massive stars. The TOPoS survey has been designed to increase the census of these stars and to provide a chemical inventory that is as detailed as ...
P. Bonifacio +22 more
semanticscholar +1 more source