scholarly journals Abundances of Iron-Group Elements in Planetary Nebulae and Consequences for Chemical Enrichment

2016 ◽  
Vol 12 (S323) ◽  
pp. 82-85
Author(s):  
Harriet L. Dinerstein ◽  
T. R. Geballe ◽  
N. C. Sterling
Keyword(s):  
Emission Line ◽  
Chemical Evolution ◽  
Planetary Nebulae ◽  
Infrared Emission ◽  
Thick Disk ◽  
Galactic Chemical Evolution ◽  
Iron Group ◽  
Chemical Enrichment ◽  
Group Species

AbstractWe have developed a method for determining elemental Fe-group abundances in planetary nebulae using an infrared emission line of Zn, the least refractory Fe-group species. Many planetary nebulae, particularly those of the Milky Way’s thick disk and bulge, display subsolar [Fe/H] (as inferred from Zn) although their abundances of α elements such as O, S, and Ar are nearly solar. We discuss the implications for determining enhancements of species synthesized by the progenitor star during the AGB (e.g.,s-process products), and for galactic chemical evolution in view of the metallicity dependence of AGB nucleosynthetic yields.

Abundance ratios & ages of stellar populations in HARPS-GTO sample

2017 ◽  
Vol 12 (S330) ◽  
pp. 156-159 ◽  
Author(s):  
E. Delgado Mena ◽  
M. Tsantaki ◽  
V. Zh. Adibekyan ◽  
S. G. Sousa ◽  
N. C. Santos ◽  
...  
Keyword(s):  
Chemical Evolution ◽  
Thin Disk ◽  
Thick Disk ◽  
Heavy Elements ◽  
Galactic Chemical Evolution ◽  
Chemical Abundances ◽  
Homogeneous Sample ◽  
Different Populations ◽  
Search Program ◽  
Cu And Zn

AbstractIn this work we present chemical abundances of heavy elements (Z>28) for a homogeneous sample of 1059 stars from HARPS planet search program. We also derive ages using parallaxes from Hipparcos and Gaia DR1 to compare the results. We study the [X/Fe] ratios for different populations and compare them with models of Galactic chemical evolution. We find that thick disk stars are chemically disjunt for Zn adn Eu. Moreover, the high-alpha metal-rich population presents an interesting behaviour, with clear overabundances of Cu and Zn and lower abundances of Y and Ba with respect to thin disk stars. Several abundance ratios present a significant correlation with age for chemically separated thin disk stars (regardless of their metallicity) but thick disk stars do not present that behaviour. Moreover, at supersolar metallicities the trends with age tend to be weaker for several elements.

scholarly journals Extragalactic planetary nebulae: Tracers of the chemical evolution of nearby galaxies

2011 ◽  
Vol 7 (S283) ◽  
pp. 251-258 ◽  
Author(s):  
Laura Magrini ◽  
Letizia Stanghellini ◽  
Denise R. Gonçalves
Keyword(s):  
Chemical Evolution ◽  
Stellar Evolution ◽  
Planetary Nebulae ◽  
Spectroscopic Studies ◽  
Disk Galaxies ◽  
Chemical Enrichment ◽  
History Of ◽  
External Galaxies ◽  
Low Metallicity ◽  
Nearby Galaxies

AbstractThe study of the chemical composition of Planetary Nebulae in external galaxies is of paramount importance for the fields of stellar evolution and chemical enrichment history of galaxies. In recent years a number of spectroscopic studies with 6-8m-class telescopes have been devoted to this subject improving our knowledge of, among other, the time-evolution of the radial metallicity gradient in disk galaxies, the chemical evolution of dwarf galaxies, and stellar evolution at low metallicity.

scholarly journals Filling factor and temperature variations in planetary nebulae

2011 ◽  
Vol 7 (S283) ◽  
pp. 468-469
Author(s):  
Manuel Peimbert ◽  
Antonio Peimbert
Keyword(s):  
Chemical Evolution ◽  
Strong Correlation ◽  
Filling Factor ◽  
Planetary Nebulae ◽  
Type I ◽  
Type Ii ◽  
Galactic Chemical Evolution ◽  
Temperature Variations

AbstractWe have found a strong correlation between small filling factors and large t2 values in planetary nebulae. We have also found that in general the filling factor for Type I PNe is smaller than for Type II PNe. These results imply that the abundance correction due to temperature inhomogeneities in general is larger for Type I PNe than for Type II PNe. This difference permits to reproduce the expected abundance difference between PNe of Type I and II predicted by Galactic chemical evolution models.

scholarly journals Planetary Nebulae and the Chemical Evolution of Galaxies

1983 ◽  
Vol 103 ◽  
pp. 463-472 ◽  
Author(s):  
Alfonso Serrano
Keyword(s):  
Star Formation ◽  
Chemical Evolution ◽  
Planetary Nebulae ◽  
Low Mass Stars ◽  
Chemical Enrichment ◽  
The Past ◽  
The Galaxy ◽  
History Of ◽  
Low Mass

Tinsley (1978) has done an excellent review that illustrates the methods and concepts that can be developed to assess the effects of planetary nebulae (PN) on the long-term history of the galaxy. Tinsley concluded that research in PN could put constraints on the past rate of star formation and provide information on chemical enrichment by low mass stars.

scholarly journals The Helium-to-Metals Enrichment Ratio in Planetary Nebulae

1993 ◽  
Vol 155 ◽  
pp. 583-583
Author(s):  
C.M.L. Chiappini ◽  
W.J. Maciel
Keyword(s):  
Chemical Evolution ◽  
Planetary Nebulae ◽  
Hii Regions ◽  
Big Bang ◽  
Enrichment Ratio ◽  
Helium Abundance ◽  
Galactic Chemical Evolution ◽  
Big Bang Theory ◽  
The Big Bang

The helium-to-metals enrichment ratio (dY/dZ) and the pregalactic helium abundance (Yp) are important parameters for the understanding of the galactic chemical evolution, and also as a cosmological test to the Big Bang theory. In this work, we present a new determination of these parameters based on a sample of galactic HII regions, HII galaxies, and planetary nebulae.

scholarly journals Spectroscopy of new Planetary Nebulae close to the galactic center

1997 ◽  
Vol 180 ◽  
pp. 414-414
Author(s):  
G.C. Van de Steene ◽  
G. H. Jacoby
Keyword(s):  
Emission Line ◽  
Galactic Center ◽  
Planetary Nebulae ◽  
Chemical Enrichment ◽  
The Galaxy ◽  
History Of ◽  
Bright Emission ◽  
Bright Emission Line

Planetary Nebulae (PN) are bright emission line objects, observable at large distances throughout the Galaxy. They serve as probes of abundance gradients and chemical enrichment history of the ISM.

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