Results 11 to 20 of about 5,445,983 (296)
Chemical abundances of the Typhon stellar stream [PDF]
Monthly Notices of the Royal Astronomical Society, 2022 ABSTRACT We present the first high-resolution chemical abundances of seven stars in the recently discovered high-energy stream Typhon. Typhon stars have apocentres r ≳ 100 kpc, making this the first detailed chemical picture of the Milky Way’s very distant stellar halo.
Alexander P Ji +4 more
openaire +3 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
Observing the signatures of AGB s-process nucleosynthesis in planetary nebulae: An origins story
Frontiers in Astronomy and Space Sciences, 2022 I relate an anecdotal history of the beginnings of a new initiative in studies of the chemical composition of planetary nebulae: namely, investigating abundances of elements beyond the iron-peak through infrared spectroscopy.
Harriet L. Dinerstein
doaj +1 more source
Chemical Tracing and the Origin of Carbon in the Galactic Disk
Universe, 2022 A basic problem in studies of the evolution of chemical elements in galaxies is the uncertainties in the yields of elements produced by different types of stars.
Bengt Gustafsson
doaj +1 more source
Chemical Evolution of CNO Abundances [PDF]
, 2003 New low and intermediate star yields calculated by Buell (1997) are evaluated by using them in a Galactic Chemical Evolution model.
Gavilan, M., Molla, M.
openaire +2 more sources
Disk evolution, element abundances and cloud properties of young gas giant planets [PDF]
, 2014 ChHc and PBR highlights financial support of the European Community under the FP7 program by an ERC starting grant. PW, IK, and WFT acknowledge funding from the European Union Seventh Framework Programme FP7-2011 under grant agreement No.
Kamp, I. +19 more
core +2 more sources
Chemical abundances and metallicity of Planetary Nebulae [PDF]
Symposium - International Astronomical Union, 1997 Confrontations of the dredge-up theory with observed patterns of chemical abundances of planetary nebulae (PNs) have been carried out by many authors (see, e.g., Kaler & Jacoby 1990, 1991; Stasińska & Tylenda 1990). Although these studies suggest that the observational abundance ratios of PNs can qualitatively be explained by the current dredge-
C. Y. Zhang, S. Kwok
openaire +1 more source
Chemical Abundances in Galactic Bulge Pn [PDF]
Symposium - International Astronomical Union, 1993 We present abundance determinations, in particular of carbon, and C/O ratios, for 11 Galactic bulge planetary nebulae (PN) based on our low resolution UV data from IUE observations and optical spectrophotometry from the Anglo-Australian Telescope. We compare the observed abundances with those predicted by dredge-up theory for the high metallicity ...
N. A. Walton +2 more
openaire +1 more source
Stellar evolution with SMC chemical abundances [PDF]
International Astronomical Union Colloquium, 1981 Evolutionary computations are presented for massive stars between 20 Mo and 100 Mo with chemical abundances holding for the Small Magellanic Cloud, i.e. X = .76 and Z = .003. Mass loss by stellar wind is taken into account during core hydrogen burning.
P. Hellings, D. Vanbeveren
openaire +1 more source
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