Results 81 to 90 of about 50,982 (241)

Novae: An Important Source of Lithium in the Galaxy

The Astrophysical Journal
The source of the Galactic lithium (Li) has long been a puzzle. With the discovery of Li in novae, extensive research has been conducted. However, there still exists a significant disparity between the observed abundance of Li in novae and the existing ...
Jun Gao, Chunhua Zhu, Guoliang Lü, Jinlong Yu, Lin Li, Helei Liu, Sufen Guo   +6 more
doaj   +1 more source

Theoretical Diagnostics for Narrow-line Regions of Active Galactic Nuclei

The Astrophysical Journal
Gas metallicity, ionization parameter, and gas pressure can affect the observed ratios of specific strong emission lines within galaxies. While the theoretical strong lines diagnostics for gas metallicity, ionization parameters, and gas pressure in star ...
Peixin Zhu, Lisa J. Kewley, Ralph S. Sutherland   +2 more
doaj   +1 more source

Alpha element abundances and gradients in the Milky Way bulge from FLAMES-GIRAFFE spectra of 650 K giants

, 2011
We obtained FLAMES-GIRAFFE spectra (R=22,500) at the ESO Very Large Telescope for 650 bulge red giant branch (RGB) stars and performed spectral synthesis to measure Mg, Ca, Ti, and Si abundances.
A. Alves-Brito, A. Gomez, A. Renzini, Alonso, Alves-Brito, Asplund, Athanassoula, B. Barbuy, Babusiaux, Babusiaux, Bagnulo, Bensby, Bensby, Bournaud, Brown, Bureau, C. Babusiaux, Carollo, Clarkson, D. Minniti, Daddi, Debattista, Debattista, Di Matteo, Elmegreen, Fukugita, Fulbright, Fulbright, Förster Schreiber, G. Battaglia, Genzel, Genzel, Gratton, Gustafsson, Hopkins, Howard, Immeli, Kormendy, Lecureur, M. Rejkuba, M. Zoccali, McWilliam, McWilliam, Meléndez, Minniti, Minniti, Minniti, Nakasato, Nataf, O. A. Gonzalez, Patsis, Peletier, Peng, Plez, Ramírez, Rangwala, Rattenbury, Reddy, Renzini, Rich, Rich, Ryde, Ryde, S. Ortolani, Samland, Shen, Sneden, Stetson, Tacconi, Udalski, V. Hill, Weinzirl, Zoccali, Zoccali, Zoccali   +74 more
core   +3 more sources

STRONTIUM ABUNDANCES IN COOL DWARF STARS OF GALACTIC THIN AND THICK DISKS

Odessa Astronomical Publications, 2016
We revise the strontium abundances in FGK stars with metallicities ranging from −1.0 < [Fe/H] < +0.3. The observed stars belong to the substructures of the Galaxy thick and thin discs.
T. I. Gorbaneva, T. V. Mishenina
doaj   +1 more source

Phosphorus Enrichment by ONe Novae in the Galaxy

The Astrophysical Journal Letters
Recent observations have shown that [P/Fe] in the Galactic stars decreases with increasing [Fe/H] for [Fe/H] ≳ − 1 whereas it is almost subsolar for [Fe/H] ≲ −2. These [P/Fe] trends with [Fe/H] have not been well reproduced by previous theoretical models
Kenji Bekki, Takuji Tsujimoto
doaj   +1 more source

Abundances from solar-flare gamma-ray line spectroscopy [PDF]

Elemental abundances of the ambient gas at the site of gamma ray line production inthe solar atmosphere are deduced using gamma ray line observations from a solar flare.
Forrest, D. J., Kozlovsky, B., Murphy, R. J., Ramaty, R.   +3 more
core   +1 more source

Nucleosynthesis: Stellar and Solar Abundances and Atomic Data [PDF]

, 2006
Abundance observations indicate the presence of often surprisingly large amounts of neutron capture (i.e., s- and r-process) elements in old Galactic halo and globular cluster stars.
Collier, Jason, Cowan, John J., DenHartog, E. A., Dodge, Homer L., Lawler, James E., Sneden, Christopher   +5 more
core   +4 more sources

HII Regions And the Protosolar Helium, Carbon, and Oxygen Abundances in the Context of Galactic Chemical Evolution [PDF]

, 2011
We present chemical evolution models of the Galactic disk with different Z-dependent yields. We find that a moderate mass loss rate for massive stars of solar metallicity produces an excellent fit to the observed C/H and C/O gradients of the Galactic ...
Carigi, Leticia, Peimbert, Manuel
core  

NO and c-C3H2 in the Outer Galaxy: High Molecular Abundances at RGC > 13 kpc

The Astrophysical Journal
Observations of the J _Ka, Kc = 4 _1,4 → 3 _0,3 , 4 _0,4 → 3 _1,3 , and 2 _2,0 → 1 _1,1 rotational lines of c-C _3 H _2 and the J = 3/2 → 1/2, Ω = 1/2 transition of NO (X ^2 Π _r ) were conducted at 2 mm toward 20 Galactic edge clouds with R _GC = 10.8 ...
L. A. Koelemay, L. M. Ziurys
doaj   +1 more source

Alfven wave scattering and the secondary to primary ratio [PDF]

The cosmic ray abundances have traditionally been used to determine the elemental and isotopic nature of galactic ray sources and average measures of propagation conditions.
Bretthorst, G. L., Margolis, S. H.
core   +1 more source