Results 71 to 80 of about 50,982 (241)

Two views of globular cluster stars in the Galactic halo

EPJ Web of Conferences, 2012
In [1] we reported the discovery in the Sloan Digital Sky Survey-II/SEGUE spectroscopic database of a small subset of halo red giants, 2.5%, with CN and CH band strengths indicative of globular-cluster-like carbon and nitrogen abundances.
Martell S.L.
doaj   +1 more source

Detection of the Actinide Th in an r-process-enhanced Star with Accretion Origin

The Astrophysical Journal
The thorium and six second-peak r -process element (56 ≤ Z ≤ 72) abundances are determined for the α -poor star LAMOST J1124+4535 based on a high-resolution spectrum obtained with the High Dispersion Spectrograph on the Subaru Telescope. The age of J1124+
Qianfan Xing, Gang Zhao, Wako Aoki, Haining Li, Jingkun Zhao, Tadafumi Matsuno, Takuma Suda   +6 more
doaj   +1 more source

PNe Abundances: Galactic Bulge versus the Disc [PDF]

Astrophysics and Space Science, 2001
We compare the abundances of He, N, O, Ar, S, and Ne, determined in a similar way, for a sample of Galactic bulge and disc planetary nebulae (PNe). We find that in all aspects — average abundances and dispersion, distribution functions, abundance relationships, and the ratio of N/O — the bulge and disc PNe are indistinguishable.
Exter, K, Barlow, MJ, Walton, NA, Clegg, RES   +3 more
openaire   +3 more sources

Features of Chemical-Element Abundances in Open Star Clusters of the Galaxy

Open Astronomy, 2016
On the basis of the authors’ compiled catalog containing spectroscopic abundances of 14 chemical elements for 90 open star clusters of the Galaxy, we show that in the young clusters not only barium but also three other studied elements of slow neutron ...
Marsakov V. A., Koval’ V. V., Gozha M. L., Shpigel’ L. V.   +3 more
doaj   +1 more source

On the abundance gradient in the galactic halo

The Astrophysical Journal, 1979
The problem of the radial gradient of heavy-element abundance in the galactic halo is investigated by considering all recent abundance measurements of globular clusters. A new compilation of high-quality (m/H) (metallicity) values for 78 clusters at all galactocentric distances supports the picture that the mean and maximum (m/H) in the halo decrease ...
R. Canterna, William E. Harris
openaire   +2 more sources

Elemental abundance survey of the Galactic thick disc [PDF]

Monthly Notices of the Royal Astronomical Society, 2006
[Abridged abstract] We have performed an abundance analysis for 176 F- and G- dwarfs of the Galactic thick disk component. Using accurate radial velocities combined with $Hipparcos$ astrometry, kinematics (U, V, and W) and Galactic orbital parameters were computed. We estimate the probability for a star to belong to the thin disk, the thick disk or the
Carlos Allende Prieto, Bacham E. Reddy, David L. Lambert   +2 more
openaire   +3 more sources

The Origins of Lithium Enhancement in Polluted White Dwarfs

The Astrophysical Journal
The bulk abundances of exoplanetesimals can be measured when they are accreted by white dwarfs. Recently, lithium from the accretion of exoplanetesimals was detected in relatively high levels in multiple white dwarfs.
Benjamin C. Kaiser, J. Christopher Clemens, Simon Blouin, Erik Dennihy, Patrick Dufour, Ryan J. Hegedus, Joshua S. Reding   +6 more
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Generic Evolution Of Deuterium And Helium-3

, 1995
The primordial abundances of deuterium and of helium-3, produced during big bang nucleosynthesis, depend sensitively on the baryon density. Thus, the observed abundances of D and \he may provide useful ``baryometers'' provided the evolution from ...
Steigman, Gary, Tosi, Monica
core   +1 more source

Abundances in the Gaseous Galactic Halo [PDF]

Highlights of Astronomy, 1998
AbstractThe well measured gas-phase abundances in the low halo suggest that this region of the Galaxy has total (gas plus dust) metal abundances which are close to those in the solar neighborhood. The gas-phase abundances in the halo are generally higher than those seen in the disk, however, this affect is likely due to the destruction of dust in the ...
openaire   +2 more sources

The Impact of Initial Composition on Massive Star Evolution and Nucleosynthesis

The Astrophysical Journal
We study the sensitivity of presupernova evolution and supernova nucleosynthesis yields of massive stars to variations of the initial composition. We use the solar abundances from Lodders, and compute two different sets of initial stellar compositions ...
Christopher West, Alexander Heger, Benoit Côté, Lev Serxner, Haoxuan Sun   +4 more
doaj   +1 more source