Results 31 to 40 of about 1,843 (251)
Theoretical models of the planetary nebula populations in galaxies: The ISM oxygen abundance when star formation stops [PDF]
Astronomy and Astrophysics Supplement Series, 1997 Using theoretical models of the planetary neb- ula populations in galaxies, we investigate whether the current oxygen abundances in bright planetary nebulae can be used to predict the oxygen abundance in the in- terstellar medium when star formation stopped. These models successfully reproduce a constant planetary nebula luminosity function (PNLF) peak
M. G. Richer, M. L. McCall, N. Arimoto
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The GALAH Survey: Dependence of elemental abundances on age and metallicity for stars in the Galactic disc [PDF]
, 2022 Using data from the GALAH survey, we explore the dependence of elemental abundances on stellar age and metallicity among Galactic disc stars. We find that the abundance of most elements can be predicted from age and [Fe/H] with an intrinsic scatter of ...
Buder, Sven +28 more
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Mapping Gas Phase Abundances and Enrichment Patterns Across Galaxy Disks
, 2019 In the coming decade we will map abundances of 1000s of HII regions within galaxies. This will allow us to understand the role of feedback and turbulence in driving the mixing and diffusion of metals in the ISM, search for over- and under-enriched ...
Kreckel, K.
core +2 more sources
Metals and dust in the neutral ISM: the Galaxy, Magellanic Clouds, and damped Lyman-
, 2018 Context. The presence of dust in the neutral interstellar medium (ISM) dramatically changes the metal abundances that we measure. Understanding the metal content in the neutral ISM, and a direct comparison between different environments, has been ...
Annalisa De Cia
core +1 more source
Influence of galactic arm scale dynamics on the molecular composition of the cold and dense ISM [PDF]
Astronomy & Astrophysics, 2018 Aim. We study the effect of large scale dynamics on the molecular composition of the dense interstellar medium during the transition between diffuse to dense clouds. Methods. We followed the formation of dense clouds (on sub-parsec scales) through the dynamics of the interstellar medium at galactic scales.
Ruaud, M. +3 more
openaire +5 more sources
ISM Abundances in Sculptor Group Dwarf Irregular Galaxies
, 2002 Using the CTIO 4-m telescope, we have obtained optical spectra of HII regions in five Sculptor Group dwarf irregular galaxies. We derive oxygen, nitrogen, and sulfur abundances from the HII region spectra. Oxygen abundances are derived via three different methods (the ``direct'' method, the empirical method guided by photoionization modeling of McGaugh
Skillman, Evan D. +2 more
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Advanced Functional Materials, EarlyView.Redox dual‐defects (Cs substitution and O vacancies) in 2D hydrated WO3 steer O2 activation toward selective singlet oxygen evolution. WO‐CO achieves 8.6–15.8 times higher 1O2 production than single‐defect or pristine catalysts, enabling efficient pollutant mineralization via a pathway‐selective photocatalytic mechanism.
Sheng‐Qi Guo +8 more
wiley +1 more source
Dependence of Gas Phase Abundances in the ISM on Column Density
, 2000 Sightlines through high- and intermediate-velocity clouds allow measurements of ionic gas phase abundances, A, at very low values of HI column density, N(HI). Present observations cover over 4 orders of magnitude in N(HI). Remarkably, for several ions we find that the A vs N(HI) relation is the same at high and low column density and that the ...
Wakker, B. P., Mathis, J. S.
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ISM chemical abundances in two intermediate-velocity clouds in the line of sight to SN 1987A
The Astronomical Journal, 1988 The earliest IUE high-resolution spectra of SN 1987A have been studied and reveal the presence of several clouds in the line of sight to the LMC. In particular, there are two clouds with radial velocities of about 130 km/s and about 180 km/s. These clouds' velocities are between those of Galactic clouds at 0-80 km/s and those of LMC gas at about 270 km/
Siobahn Morgan, Erika Bohm-Vitense
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UV Capabilities to Probe the Formation of Planetary Systems: From the ISM to Planets [PDF]
, 2006 Planetary systems are angular momentum reservoirs generated during star formation. Solutions to three of the most important problems in contemporary astrophysics are needed to understand the entire process of planetary system formation: The physics of ...
Gomez de Castro, Ana +7 more
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