Nucleosynthesis in explosions of high metallicity supermassive objects

2005 ◽  
pp. 233-242 ◽  
Author(s):  
Wolfgang Hillebrandt ◽  
Friedrich-Karl Thielemann ◽  
Norbert Langer
Keyword(s):  
High Metallicity

scholarly journals Confirming known planetary trends using a photometrically selected Kepler sample

2020 ◽  
Author(s):  
Jonah T Hansen ◽  
Luca Casagrande ◽  
Michael J Ireland ◽  
Jane Lin
Keyword(s):  
Sample Size ◽  
Robust Statistics ◽  
Narrow Band ◽  
Small Sample Size ◽  
Small Sample ◽  
Fitting Algorithm ◽  
Statistical Studies ◽  
The Rich ◽  
Host Stars ◽  
High Metallicity

Abstract Statistical studies of exoplanets and the properties of their host stars have been critical to informing models of planet formation. Numerous trends have arisen in particular from the rich Kepler dataset, including that exoplanets are more likely to be found around stars with a high metallicity and the presence of a “gap” in the distribution of planetary radii at 1.9 R⊕. Here we present a new analysis on the Kepler field, using the APOGEE spectroscopic survey to build a metallicity calibration based on Gaia, 2MASS and Strömgren photometry. This calibration, along with masses and radii derived from a Bayesian isochrone fitting algorithm, is used to test a number of these trends with unbiased, photometrically derived parameters, albeit with a smaller sample size in comparison to recent studies. We recover that planets are more frequently found around higher metallicity stars; over the entire sample, planetary frequencies are 0.88 ± 0.12 percent for [Fe/H] < 0 and 1.37 ± 0.16 percent for [Fe/H] ≥ 0 but at two sigma we find that the size of exoplanets influences the strength of this trend. We also recover the planet radius gap, along with a slight positive correlation with stellar mass. We conclude that this method shows promise to derive robust statistics of exoplanets. We also remark that spectrophotometry from Gaia DR3 will have an effective resolution similar to narrow band filters and allow to overcome the small sample size inherent in this study.

scholarly journals Unusually High Metallicity Host Of The Dark LGRB 051022

2009 ◽  
Author(s):  
J. F. Graham ◽  
A. S. Fruchter ◽  
L. J. Kewley ◽  
E. M. Levesque ◽  
A. J. Levan ◽  
...  
Keyword(s):  
High Metallicity

scholarly journals Chemical Abundances in Galactic Bulge Pn

1993 ◽  
Vol 155 ◽  
pp. 581-581 ◽  
Author(s):  
N.A. Walton ◽  
M.J. Barlow ◽  
R.E.S. Clegg
Keyword(s):  
Galactic Disk ◽  
Planetary Nebulae ◽  
Solar Neighbourhood ◽  
Galactic Bulge ◽  
Low Resolution ◽  
Chemical Abundances ◽  
The Mean ◽  
Optical Spectrophotometry ◽  
High Metallicity

We present abundance determinations, in particular of carbon, and C/O ratios, for 11 Galactic bulge planetary nebulae (PN) based on our low resolution UV data from IUE observations and optical spectrophotometry from the Anglo-Australian Telescope. We compare the observed abundances with those predicted by dredge-up theory for the high metallicity Galactic bulge. The sample abundances are also contrasted with the abundances found for PN in the Galactic disk. The mean C/O ratio for the bulge PN is significantly lower than that found for Galactic disk PN. Further, we present an abundance analysis of the very metal-poor bulge PN M2-29. From an analysis of the differential extinction found from the observed ratios of the He ii 1640,4686Å lines, we find that the ultraviolet reddening law towards the bulge is steeper than in the solar neighbourhood.

scholarly journals The WAGGS project-III. Discrepant mass-to-light ratios of Galactic globular clusters at high metallicity

2020 ◽  
Vol 492 (3) ◽  
pp. 3859-3871 ◽  
Author(s):  
H Dalgleish ◽  
S Kamann ◽  
C Usher ◽  
H Baumgardt ◽  
N Bastian ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Stellar Population ◽  
Milky Way ◽  
Population Models ◽  
Theoretical Predictions ◽  
Field Unit ◽  
Stellar Masses ◽  
Kinematic Information ◽  
High Metallicity ◽  
Integral Field

ABSTRACT Observed mass-to-light ratios (M/L) of metal-rich globular clusters (GCs) disagree with theoretical predictions. This discrepancy is of fundamental importance since stellar population models provide the stellar masses that underpin most of extragalactic astronomy, near and far. We have derived radial velocities for 1622 stars located in the centres of 59 Milky Way GCs – 12 of which have no previous kinematic information – using integral-field unit data from the WAGGS project. Using N-body models, we determine dynamical masses and M/LV for the studied clusters. Our sample includes NGC 6528 and NGC 6553, which extend the metallicity range of GCs with measured M/L up to [Fe/H] ∼ −0.1 dex. We find that metal-rich clusters have M/LV more than two times lower than what is predicted by simple stellar population models. This confirms that the discrepant M/L–[Fe/H] relation remains a serious concern. We explore how our findings relate to previous observations, and the potential causes for the divergence, which we conclude is most likely due to dynamical effects.

scholarly journals Bi-abundance photoionization models of planetary nebulae: determining the amount of oxygen in the metal-rich component

2020 ◽  
Vol 497 (3) ◽  
pp. 3363-3380 ◽  
Author(s):  
V Gómez-Llanos ◽  
C Morisset
Keyword(s):  
Heavy Element ◽  
Volume Fraction ◽  
Planetary Nebulae ◽  
Line Ratio ◽  
Small Contribution ◽  
Rich Region ◽  
Normal Region ◽  
Cold Metal ◽  
High Metallicity

ABSTRACT We study the hypothesis of high-metallicity clumps being responsible for the abundance discrepancy found in planetary nebulae between the values obtained from recombination and collisionally excited lines. We generate grids of photoionization models combining cold metal-rich clumps emitting the heavy element recombination lines, embedded in a normal metallicity region responsible for the forbidden lines. The two running parameters of the grid are the metallicity of the clumps and its volume fraction relative to the whole nebula. We determine the density and temperatures (from the Balmer jump and the [O iii] 5007/4363 Å line ratio) and the ionic abundances from the collisional and recombination lines, as an observer would do. The metallicity of the near-to-solar region is recovered, while the metallicity of the clumps is systematically underestimated by up to two orders of magnitude. This is mainly because most of the Hβ emission is coming from the ‘normal’ region, and only the small contribution emitted by the metal-rich clumps should be used. We find that a given ADF(O++) can be reproduced by a small amount of rich clumps, or a bigger amount of less rich clumps. Finally, comparing with the observations of NGC 6153, we find two models that reproduce its ADF(O++) and the observed electron temperatures. We determine the fraction of oxygen embedded in the metal-rich region (with a fraction of volume less than 1 per cent) to be roughly between 25 per cent and 60 per cent of the total amount of oxygen in the nebula (a few 10−3M⊙).

scholarly journals Solar Models in Light of New High Metallicity Measurements from Solar Wind Data

2017 ◽  
Vol 839 (1) ◽  
pp. 55 ◽  
Author(s):  
Sunny Vagnozzi ◽  
Katherine Freese ◽  
Thomas H. Zurbuchen
Keyword(s):  
Solar Wind ◽  
Wind Data ◽  
High Metallicity

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

2016 ◽  
Vol 25 (1) ◽  
pp. 1-9
Author(s):  
V. A. Marsakov ◽  
V. V. Koval’ ◽  
M. L. Gozha ◽  
L. V. Shpigel’
Keyword(s):  
Neutron Capture ◽  
Chemical Elements ◽  
Star Clusters ◽  
Slow Neutron ◽  
Open Star Clusters ◽  
Element Abundances ◽  
Open Star ◽  
The Galaxy ◽  
Relative Abundances ◽  
High Metallicity

AbstractOn 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-capture, Y, La, and Ce, reveal higher relative abundances than those in the field stars, with differences beyond the error limits. We also find that, at high metallicity ([Fe/H]> −0.1), the relative abundances of the

scholarly journals Nuclear Stellar Disks in E/S0 Galaxies

1997 ◽  
Vol 163 ◽  
pp. 626-629
Author(s):  
Walter Jaffe ◽  
Frank van den Bosch
Keyword(s):  
Black Hole ◽  
Virgo Cluster ◽  
Lower Mass ◽  
Central Black Hole ◽  
Color Gradients ◽  
Different Color ◽  
S0 Galaxies ◽  
High Metallicity

AbstractNew HST images and spectra of the nuclear disks in two Virgo Cluster E/S0 galaxies reveal that they were probably formed together with their parent galaxies. The two galaxies show very different color gradients. This is most likely caused by the escape of high metallicity gas from early stars in the lower mass galaxy. One galaxy shows strong kinematic evidence for a massive central black hole.

Population gradients in dwarf spheroidal galaxies KKs 3 and ESO 269-66

2018 ◽  
Vol 14 (S344) ◽  
pp. 420-421
Author(s):  
M. E. Sharina ◽  
L. N. Makarova ◽  
D. I. Makarov
Keyword(s):  
Surface Density ◽  
Globular Clusters ◽  
Stellar Populations ◽  
Density Profiles ◽  
Dwarf Spheroidal Galaxies ◽  
Star Forming ◽  
Central Regions ◽  
Low Metallicity ◽  
High Metallicity ◽  
Spheroidal Galaxies

AbstractWe compare the properties of stellar populations for globular clusters (GCs) and field stars in two dwarf spheroidal galaxies (dSphs): ESO269-66, a close neighbour of NGC5128, and KKs3, one of the few isolated dSphs within 10 Mpc. We analyse the surface density profiles of low and high metallicity (blue and red) stars in two galaxies using the Sersic law. We argue that 1) the density profiles of red stars are steeper than those of blue stars, which evidences in favour of the metallicity and age gradients in dSphs; 2) globular clusters in KKs3 and ESO 269-66 contain 4 and 40 percent of all stars with [Fe / H] ~ 1.6 dex and the age of 12 Gyr, correspondingly. Therefore, GCs are relics of the first powerful star-forming bursts in the central regions of the galaxies. KKs 3 has lost a smaller percentage of old low-metallicity stars than ESO269-66, probably, thanks to its isolation.

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