Elemental Abundances in Evolved Supergiants. II. The Young Clusters [CLC]h[/CLC] and χ Persei

2000 ◽  
Vol 119 (4) ◽  
pp. 1839-1847 ◽  
Author(s):  
Guillermo Gonzalez ◽  
George Wallerstein
Keyword(s):  
Elemental Abundances ◽  
Young Clusters

scholarly journals Elemental abundances of low-mass stars in the young clusters 25 Orionis andλ Orionis

2011 ◽  
Vol 530 ◽  
pp. A19 ◽  
Author(s):  
K. Biazzo ◽  
S. Randich ◽  
F. Palla ◽  
C. Briceño
Keyword(s):  
Low Mass Stars ◽  
Elemental Abundances ◽  
Low Mass ◽  
Young Clusters

Elemental Abundances in Five Stars in M54, A Globular Cluster Associated with the Sagittarius Galaxy

1999 ◽  
Vol 118 (3) ◽  
pp. 1245-1251 ◽  
Author(s):  
Jeffery A. Brown ◽  
George Wallerstein ◽  
Guillermo Gonzalez
Keyword(s):  
Globular Cluster ◽  
Elemental Abundances

scholarly journals The bimodal [Mg/Fe] versus [Fe/H] bulge sequence as revealed by APOGEE DR14

2019 ◽  
Vol 626 ◽  
pp. A16 ◽  
Author(s):  
A. Rojas-Arriagada ◽  
M. Zoccali ◽  
M. Schultheis ◽  
A. Recio-Blanco ◽  
G. Zasowski ◽  
...  
Keyword(s):  
Fundamental Parameters ◽  
Elemental Abundances ◽  
Data Release ◽  
Bulge Region ◽  
Solar Metallicity ◽  
Inner Region ◽  
Clean Sample ◽  
Metallicity Distribution ◽  
Single Sequence

Context. The Galactic bulge has a bimodal metallicity distribution function: different kinematic, spatial, and, potentially, age distributions characterize the metal-poor and metal-rich components. Despite this observed dichotomy, which argues for different formation channels for those stars, the distribution of bulge stars in the α-abundance versus metallicity plane has been found so far to be a rather smooth single sequence. Aims. We use data from the fourteenth data release of the APOGEE spectroscopic survey (DR14) to investigate the distribution in the Mg abundance (as tracer of the α-elements)-versus-metallicity plane of a sample of stars selected to be in the inner region of the bulge. Methods. A clean sample has been selected from the DR14 using a set of data- and pipeline-flags to ensure the quality of their fundamental parameters and elemental abundances. An additional selection made use of computed spectro-photometric distances to select a sample of likely bulge stars as those with RGC ≤ 3.5 kpc. We adopt magnesium abundance as an α-abundance proxy for our clean sample as it has been proven to be the most accurate α-element as determined by ASPCAP, the pipeline for data products from APOGEE spectra. Results. From the distribution of our bulge sample in the [Mg/Fe]-versus-[Fe/H] plane, we found that the sequence is bimodal. This bimodality is given by the presence of a low-Mg sequence of stars parallel to the main high-Mg sequence over a range of ∼0.5 dex around solar metallicity. The two sequences merge above [Fe/H] ∼ 0.15 dex into a single sequence whose dispersion in [Mg/Fe] is larger than either of the two sequences visible at lower metallicity. This result is confirmed when we consider stars in our sample that are inside the bulge region according to trustworthy Gaia DR2 distances.

scholarly journals ASCA observations of clusters of galaxies

1996 ◽  
Vol 175 ◽  
pp. 363-366
Author(s):  
Koujun Yamashita
Keyword(s):  
High Resolution Spectroscopy ◽  
Atomic Processes ◽  
Spectral Fitting ◽  
Elemental Abundances ◽  
Hot Plasma ◽  
Emission Models ◽  
Formation And Evolution ◽  
Collisional Ionization ◽  
Intracluster Gas

X-ray emissions from clusters are most likely originated from a thin hot plasma in a collisional ionization equilibrium. The optical depth of continuum component is order of 10–3, whereas that of emission lines is around unity. Present emission models used for spectral fitting can not estimate this effect, so that the determination of elemental abundances seems to include large uncertainty. The high resolution spectroscopy with ASCA gives a clue to investigate the physical state of hot intracluster gas and a impact to reconsider the basic atomic processes. This is important issue to deeply understand the structure, formation and evolution of clusters, and the origin of intracluster gas.

scholarly journals Lithium abundances in the α Persei Cluster

2009 ◽  
Vol 5 (S268) ◽  
pp. 339-340
Author(s):  
Sushma V. Mallik ◽  
Suchitra C. Balachandran ◽  
David L. Lambert
Keyword(s):  
High Resolution ◽  
Cluster Membership ◽  
Young Clusters ◽  
Larger Sample

AbstractAs a sequel to the Li observations by Balachandran, Lambert & Stauffer (1988, 1996) in 35 stars of the 50 Myr old cluster α Persei, we have obtained and analyzed high resolution spectra of another 51 stars. Following a reconsideration of the cluster membership of the stars (Prosser 1992, Makarov 2006, Mermilliod et al. 2008, and Patience et al. 2002), we discuss the Li abundances for 70 stars. With our larger sample, we reexamine the question of whether the scatter in Li abundance at a given Teff seen in young clusters at cool temperatures is real or not.

scholarly journals Quasar Elemental Abundances at High Redshifts

2003 ◽  
Vol 589 (2) ◽  
pp. 722-732 ◽  
Author(s):  
M. Dietrich ◽  
F. Hamann ◽  
J. C. Shields ◽  
A. Constantin ◽  
J. Heidt ◽  
...  
Keyword(s):  
Elemental Abundances

Identification of the origin of silicate, magnetic and glass spherules from trace elemental abundances by INAA

1987 ◽  
Vol 114 (2) ◽  
pp. 329-335 ◽  
Author(s):  
S. L. Ma ◽  
C. F. Chai ◽  
X. Y. Mao ◽  
H. C. Peng ◽  
K. Lu ◽  
...  
Keyword(s):  
Elemental Abundances ◽  
Trace Elemental

scholarly journals Do you know the extinction in your young massive cluster?

2015 ◽  
Vol 12 (S316) ◽  
pp. 137-138
Author(s):  
Guido De Marchi ◽  
Nino Panagia ◽  
Elena Sabbi
Keyword(s):  
Interstellar Medium ◽  
Local Extinction ◽  
Type Ii ◽  
Effective Temperatures ◽  
Young Clusters ◽  
Massive Clusters ◽  
Massive Cluster

Up to ages of ~ 100 Myr, massive clusters are still swamped in large amounts of gas and dust, with considerable and uneven levels of extinction. At the same time, large grains (ices?) produced by type II supernovae profoundly alter the interstellar medium (ISM), thus resulting in extinction properties very different from those of the diffuse ISM. To obtain physically meaningful parameters of stars, from basic luminosities and effective temperatures to masses and ages, we must understand and measure the local extinction law. This problem affects all the massive young clusters discussed in his volume.

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