Results 21 to 30 of about 464,371 (256)
Geosciences, 2023 Local geological and tectonic processes have been pivotal in shaping the diverse sedimentation patterns observed in Jordan, forming sub-basins characterized by elevated organic matter content (TOC). This study aims to characterize the Maastrichtian basin,
Albesher Hussein +2 more
doaj +1 more source
New calibrations for abundance determinations in HII regions [PDF]
, 2016 Simple relations for deriving the oxygen abundance in HII regions with intensities of the three strong emission lines R_2, R_3, and N_2 (R calibration) or S_2, R_3, and N_2 (S calibration) in their spectra are suggested.
Grebel, E. K., Pilyugin, L. S.
core +2 more sources
Light Elements in the Universe
Frontiers in Astronomy and Space Sciences, 2021 Due to their production sites, as well as to how they are processed and destroyed in stars, the light elements are excellent tools to investigate a number of crucial issues in modern astrophysics: from stellar structure and non-standard processes at work
Sofia Randich, Laura Magrini
doaj +1 more source
Planetary Nebulae: Abundances and Abundance Gradients [PDF]
, 2000 In this work, a review is given of some recent results and problems involved in the determination of chemical abundances of galactic planetary nebulae, particularly regarding disk and bulge objects.
openaire +2 more sources
Shallow extra mixing in solar twins inferred from Be abundances [PDF]
, 2015 Lithium and beryllium are destroyed at different temperatures in stellar interiors. As such, their relative abundances offer excellent probes of the nature and extent of mixing processes within and below the convection zone.
Asplund, M. +7 more
core +2 more sources
Cu I resonance lines in turn-off stars of NGC 6752 and NGC 6397. Effects of granulation from CO5BOLD models [PDF]
, 2010 Context. Copper is an element whose interesting evolution with metallicity is not fully understood. Observations of copper abundances rely on a very limited number of lines, the strongest are the Cu I lines of Mult.
Bonifacio, Piercarlo +2 more
core +5 more sources
Constraints on the nucleosynthesis of refractory nuclides in galactic cosmic rays [PDF]
, 2001 Abundances of the isotopes of the refractory elements Ca, Fe, Co, and Ni in the galactic cosmic-ray source are compared with corresponding abundances in solar-system matter.
Binns, W. R. +12 more
core +1 more source
Chemical fingerprints of He-sdO stars
Open Astronomy, 2018 The chemical composition of helium-rich hot subluminous O stars plays an important role to understand and model their formation history. We present a spectroscopic analysis of four He-sdO stars,CD-31° 4800, [CW83] 0904- 02, LSS 1274 and LS IV +10° 9. The
Schindewolf Markus +5 more
doaj +1 more source
The solar wind heavy ion composition in the ascending phases of the solar cycles 23 and 25
Frontiers in Astronomy and Space SciencesThe approximately 11-year solar cycle has been shown to impact the heavy ion composition of the solar wind, even when accounting for streams of differing speeds; however, the heavy ion composition observed between the same specific phases of a past solar
D. T. Carpenter +8 more
doaj +1 more source
Integral Field Spectroscopy of Planetary Nebulae with MUSE
Galaxies, 2020 The Multi-Unit Spectroscopic Explorer (MUSE) is a large integral field unit mounted on the ESO Very Large Telescope. Its spatial (60 arcsecond field) and wavelength (4800–9300Å) coverage is well suited to detailed imaging spectroscopy of extended ...
Jeremy R. Walsh, Ana Monreal-Ibero
doaj +1 more source