Results 21 to 30 of about 612,500 (304)

Theoretical Predictions of Surface Light Element Abundances in Protostellar and Pre-Main Sequence Phase

Frontiers in Astronomy and Space Sciences, 2021
Theoretical prediction of surface stellar abundances of light elements–lithium, beryllium, and boron–represents one of the most interesting open problems in astrophysics.
E. Tognelli, E. Tognelli, S. Degl’Innocenti, S. Degl’Innocenti, P. G. Prada Moroni, P. G. Prada Moroni, L. Lamia, L. Lamia, L. Lamia, R. G. Pizzone, A. Tumino, A. Tumino, C. Spitaleri, C. Spitaleri, A. Chiavassa   +14 more
doaj   +1 more source

Nucleosynthesis Predictions and High-Precision Deuterium Measurements

Universe, 2017
Two new high-precision measurements of the deuterium abundance from absorbers along the line of sight to the quasar PKS1937–1009 were presented. The absorbers have lower neutral hydrogen column densities (N(HI) ≈ 18 cm − 2 ) than for previous ...
Signe Riemer-Sørensen, Espen Sem Jenssen   +1 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

High-Resolution Spectroscopy of Cool Carbon-Rich and Metal-Poor Star HD 209621

Open Astronomy, 2012
Element abundances for HD 209621 obtained earlier display significant discrepancies, especially in the case of CNO and neutron-capture elements. Therefore we performed a detailed analysis of chemical composition of this star using a new high-resolution ...
Matrozis E., Začs L., Barzdis A.
doaj   +1 more source

Viruses in aquatic ecosystems: important advancements of the last 20 years and prospects for the future in the field of microbial oceanography and limnology

Advances in Oceanography and Limnology, 2010
Over the last two decades, viruses in aquatic systems have been observed to modify, influence and control aquatic systems. Since the determination decades ago that viruses were abundant in aquatic ecosystems, researchers have demonstrated that viruses ...
Stéphan Jacquet, Takeshi Miki, Rachel Noble, Peter Peduzzi, Steven Wilhelm   +4 more
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

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, Caffau, Elisabetta, Ludwig, Hans-Günter   +2 more
core   +5 more sources

Constraining solar abundances using helioseismology [PDF]

, 2004
Recent analyses of solar photospheric abundances suggest that the oxygen abundance in the solar atmosphere needs to be revised downwards. In this study we investigate the consequence of this revision on helioseismic analyses of the depth of the solar ...
Antia, H. M., Basu, Sarbani
core   +2 more sources

The solar wind heavy ion composition in the ascending phases of the solar cycles 23 and 25

Frontiers in Astronomy and Space Sciences
The 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, S. T. Lepri, L. Zhao, R. M. Dewey, J. M. Raines, S. Livi, S. Livi, A. B. Galvin, L. M. Kistler   +8 more
doaj   +1 more source

Chemical Analysis of the Brightest Star of the Cetus II Ultrafaint Dwarf Galaxy Candidate

The Astrophysical Journal, 2023
We present a detailed chemical abundance analysis of the brightest star in the ultrafaint dwarf (UFD) galaxy candidate Cetus II from high-resolution Magellan/MIKE spectra.
K. B. Webber, T. T. Hansen, J. L. Marshall, J. D. Simon, A. B. Pace, B. Mutlu-Pakdil, A. Drlica-Wagner, C. E. Martínez-Vázquez, M. Aguena, S. S. Allam, O. Alves, E. Bertin, D. Brooks, A. Carnero Rosell, J. Carretero, L. N. da Costa, J. De Vicente, P. Doel, I. Ferrero, D. Friedel, J. Frieman, J. García-Bellido, G. Giannini, D. Gruen, R. A. Gruendl, S. R. Hinton, D. L. Hollowood, K. Honscheid, K. Kuehn, J. Mena-Fernández, F. Menanteau, R. Miquel, R. L. C. Ogando, M. E. S. Pereira, A. Pieres, A. A. Plazas Malagón, E. Sanchez, B. Santiago, J. Allyn Smith, M. Smith, E. Suchyta, G. Tarle, C. To, N. Weaverdyck, B. Yanny   +44 more
doaj   +1 more source