Results 11 to 20 of about 226,407 (198)

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

Precision Chemical Abundance Measurements [PDF]

Proceedings of the International Astronomical Union, 2012
AbstractThis talk covers preliminary work in which we apply a strictly differential line-by-line chemical abundance analysis to high quality UVES spectra of the globular cluster NGC 6752. We achieve extremely high precision in the measurement of relative abundance ratios.
Yong, David, Grundahl, Frank, Meléndez, Jorge, Norris, John E.   +3 more
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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.
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Connecting the primordial and Galactic deuterium abundances [PDF]

, 2007
The deuterium abundances inferred from observations of the interstellar medium within 1-2 kpc of the Sun range over a factor of three and the corresponding oxygen abundances show an even larger dispersion.
Romano, Donatella, Steigman, Gary, Tosi, Monica   +2 more
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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, Lina Necib, Alexander P. Ji, Xiaowei Ou, Mariangela Lisanti, Mithi A. C. de los Reyes, Allison L. Strom, Mimi Truong   +7 more
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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., de Graauw T., Feldman U., Fluks M. A., Grevesse N., J. Bernard‐Salas, J. R. Houck, Monk D. J., P. W. Morris, Pena M., S. Gutenkunst, S. R. Pottasch, Zijlstra A. A.   +12 more
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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
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Chemical Processes in Protoplanetary Disks [PDF]

, 2010
We have developed a high resolution combined physical and chemical model of a protoplanetary disk surrounding a typical T Tauri star. Our aims were to use our model to calculate the chemical structure of disks on small scales (sub-milli-arcsecond in the ...
Aikawa, Bottinelli, Carr, Catherine Walsh, Ceccarelli, Ceccarelli, D'Alessio, Dutrey, Dutrey, Gibb, Guilloteau, Hasegawa, Henning, Hideko Nomura, Johns-Krull, Kastner, Lahuis, Lynden-Bell, Léger, Najita, Nomura, Pascucci, Qi, Qi, Qi, Qi, Salyk, Semenov, Shakura, T. J. Millar, Valenti, Weingartner, Willacy, Willacy, Willacy, Willacy, Yamamoto, Öberg, Öberg   +38 more
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Constraining cosmic scatter in the Galactic halo through a differential analysis of metal-poor stars [PDF]

, 2017
© ESO 2017.Context. The chemical abundances of metal-poor halo stars are important to understanding key aspects of Galactic formation and evolution. Aims.
Amanda Karakas, Andrievsky, Andrievsky, Andrievsky, Andrievsky, Andrievsky, Aoki, Aoki, Arnone, Asplund, Asplund, Audouze, Baumueller, Baumueller, Bensby, Bergemann, Bergemann, Biazzo, Boesgaard, Bonifacio, Bonifacio, Busso, Busso, Carlos, Caughlan, Cayrel, Cescutti, Chiaki Kobayashi, Chiappini, Chieffi, Civitarese, Coc, Coc, Coc, Cohen, Cowan, Cyburt, Eggen, Ferraro, Ferraro, Fishlock, François, Frischknecht, Fu, Gustafsson, Hampel, Hannaford, Hansen, Hartog, Heger, Henrique Reggiani, Herwig, Hollek, Hou, Iocco, Jacobson, Ji, Jorge Meléndez, Karakas, Karakas, Keller, Kim, Kobayashi, Kobayashi, Kobayashi, Kohri, Lai, Lawler, Lind, Lind, Liu, Liu, Maeda, McCrea, McWilliam, Meléndez, Meléndez, Meléndez, Meléndez, Meyer, Meynet, Monroe, Nissen, Nissen, Nissen, Nomoto, Norris, Norris, O’Malley, Pignatari, Placco, Placco, Placco, Pllumbi, Ramírez, Ramírez, Ramírez, Ramírez, Ramírez, Ramírez, Reggiani, Richard, Roederer, Ryan, Ryan, Ryan, Salvati, Santucci, Scholz, Schuster, Searle, Shigeyama, Sills, Sitnova, Sneden, Spina, Spite, Spite, Spite, Suda, Suda, Thielemann, Tucci Maia, Tucci Maia, Umeda, Vinicius Placco, Wood, Yamada, Yi, Yong, Zhao, Önehag   +131 more
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