scholarly journals Chemical composition of stars with massive planets*

2021 ◽  
Author(s):  
T Mishenina ◽  
N Basak ◽  
V Adibekyan ◽  
C Soubiran ◽  
V Kovtyukh
Keyword(s):  
Chemical Composition ◽  
High Resolution ◽  
Chemical Evolution ◽  
Planet Formation ◽  
Galactic Chemical Evolution ◽  
Lithium Abundance ◽  
Mean Values ◽  
Planetary Mass ◽  
Iron Abundance ◽  
The Mean

Abstract Stellar parameters of 25 planet-hosting stars and abundances of Li, C, O, Na, Mg, Al, S, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Ni, Zn, Y, Zr, Ba, Ce, Pr, Nd, Sm and Eu, were studied based on homogeneous high resolution spectra and uniform techniques. The iron abundance [Fe/H] and key elements (Li, C, O, Mg, Si) indicative of the planet formation, as well as the dependencies of [El/Fe] on Tcond, were analyzed. The iron abundances determined in our sample stars with detected massive planets range within –0.3 < [Fe/H] < 0.4. The behaviour of [C/Fe], [O/Fe], [Mg/Fe] and [Si/Fe] relative to [Fe/H] is consistent with the Galactic Chemical Evolution trends. The mean values of C/O and [C/O] are <C/O> = 0.48 ±0.07 and <[C/O]> = –0.07 ±0.07, which are slightly lower than solar ones. The Mg/Si ratios range from 0.83 to 0.95 for four stars in our sample and from 1.0 to 1.86 for the remaining 21 stars. Various slopes of [El/Fe] vs. Tcond were found. The dependencies of the planetary mass on metallicity, the lithium abundance, the C/O and Mg/Si ratios, and also on the [El/Fe]–Tcond slopes were considered.

scholarly journals CNO abundances in giants of the peculiar globular cluster NGC 1851

2015 ◽  
Vol 11 (S317) ◽  
pp. 352-353
Author(s):  
G. Tautvaišienė ◽  
A. Drazdauskas ◽  
C. Lardo ◽  
S. L. Martell ◽  
E. Pancino ◽  
...  
Keyword(s):  
High Resolution ◽  
Globular Cluster ◽  
Mean Values ◽  
Significant Difference ◽  
The Mean ◽  
Cno Abundances

AbstractWe provide CNO and Fe abundance investigations for a sample of up to 45 NGC 1851 giants. High-resolution spectra were obtained with the VLT UVES spectrograph in the framework of the Gaia-ESO Survey. The stars in our sample can be separated into two groups with a difference of 0.1 dex in the mean metallicity, 0.3 dex in the mean C/N, and no significant difference in the mean values of C+N+O.

scholarly journals The Composition of H II Regions in the Magellanic Clouds

1984 ◽  
Vol 108 ◽  
pp. 353-361 ◽  
Author(s):  
Reginald J. Dufour
Keyword(s):  
Chemical Composition ◽  
Chemical Evolution ◽  
Magellanic Clouds ◽  
The State ◽  
H Ii Regions ◽  
Galactic Chemical Evolution

The state of our knowledge concerning the chemical composition of H II regions in the Magellanic Clouds is reviewed. New abundances derived from all modern published spectroscopy are presented. Some of the implications of the results regarding the nucleosynthesis of the elements and galactic chemical evolution are noted.

Recent Results from a High-Resolution Spectroscopic Follow-up Survey of Classical Novæ

2017 ◽  
Vol 14 (S339) ◽  
pp. 61-64
Author(s):  
L. Izzo
Keyword(s):  
High Resolution ◽  
Chemical Evolution ◽  
Galactic Chemical Evolution ◽  
Classical Novae

AbstractThis talk presented and discussed some recent results obtained from a photometric and spectroscopic optical follow-up survey of bright classical novæ. The survey concerned the role of those objects in Galactic chemical evolution, with particular attention to the production of lithium.

S119 – Tongue-holding Maneuver Studied by High-resolution Manometry

2008 ◽  
Vol 139 (2_suppl) ◽  
pp. P117-P117
Author(s):  
Hiroshi Umeki ◽  
Kenji Takasaki ◽  
Kaori Enatsu ◽  
Fujinobu Tanaka ◽  
Hidetaka Kumagami ◽  
...  
Keyword(s):  
Standard Deviation ◽  
High Resolution ◽  
Mean Value ◽  
Upper Esophageal Sphincter ◽  
Mean Values ◽  
High Resolution Manometry ◽  
Maximum Value ◽  
Asymptomatic Adult ◽  
The Mean ◽  
Esophageal Sphincter

Objectives This study aimed to investigate the effects of a tongue-holding maneuver (THM) during swallowing, using a novel high-resolution manometry (HRM) system. Methods 27 asymptomatic adult Japanese controls were studied. A solid-state HRM assembly with 36 circumferential sensors spaced 1 cm apart was positioned to record pressures during swallowing from the velopharynx to the upper esophagus. The maximum values of the dry swallowing pressures at meso-hypopharynx, the upper esophageal sphincter (UES) and the mean values at meso-hypopharynx with and without THM were measured. Results The maximum values of dry swallowing pressures with and without THM were 195.0±77.2 (mmHg, mean ± standard deviation), and 178.1±53.0 at the meso-hypopharynx, and 213.4±74.0 and 190.0±95.0 at the UES, respectively. The mean values with and without THM at meso-hypopharynx were 47.4±11.9, and 44.0±11.2, respectively. The maximum value at UES (p=0.0347), and the mean value at the meso-hypopharynx (p=0.0124) of dry swallowing pressures with THM were significantly higher than those without THM. Conclusions These findings indicate that the THM has a potential to facilitate compensatory swallowing power at the pharynx and upper esophagus. HRM will provide us with important information about the swallowing physiology, and pathophysiology along the velopharynx, and upper esophagus.

High-Resolution Spectroscopy of 15 Metal-Poor Stars

2005 ◽  
Vol 277-279 ◽  
pp. 851-856
Author(s):  
Hyun Jin Jeong ◽  
Jae Woo Lee ◽  
Sug Whan Kim ◽  
A Ram Kang
Keyword(s):  
High Resolution ◽  
Mean Value ◽  
Solar Neighborhood ◽  
High Resolution Spectroscopy ◽  
Chemical Abundance ◽  
Dwarf Stars ◽  
Mean Values ◽  
Elemental Abundances ◽  
The Mean ◽  
Good Agreement

We present high-resolution chemical abundance results of 15 metal-poor dwarf stars in the solar neighborhood. Our metallicity measurements are in a good agreement with previous estimates. The stars under investigation have metallicities ranging from -1.6 to -2.8 with the mean value of [Fe/H] = -2.28. The mean values of elemental abundances are [O/Fe] = 0.73, [Na/Fe] = -0.16, [Ca/Fe] = 0.28, and [Ti/Fe] = 0.60. Our results are found to be consistent with those of giant metal-poor stars.

scholarly journals Galactic Chemical Evolution of Radioactive Isotopes with an s-process Contribution

2022 ◽  
Vol 924 (1) ◽  
pp. 10
Author(s):  
Thomas C. L. Trueman ◽  
Benoit Côté ◽  
Andrés Yagüe López ◽  
Jacqueline den Hartogh ◽  
Marco Pignatari ◽  
...  
Keyword(s):  
Chemical Evolution ◽  
Average Length ◽  
Asymptotic Giant Branch ◽  
Radioactive Isotopes ◽  
Agb Stars ◽  
Galactic Chemical Evolution ◽  
Early Solar System ◽  
Self Consistent ◽  
Consistent Solution ◽  
The Mean

Abstract Analysis of inclusions in primitive meteorites reveals that several short-lived radionuclides (SLRs) with half-lives of 0.1–100 Myr existed in the early solar system (ESS). We investigate the ESS origin of 107Pd, 135Cs, and 182Hf, which are produced by slow neutron captures (the s-process) in asymptotic giant branch (AGB) stars. We modeled the Galactic abundances of these SLRs using the OMEGA+ galactic chemical evolution (GCE) code and two sets of mass- and metallicity-dependent AGB nucleosynthesis yields (Monash and FRUITY). Depending on the ratio of the mean-life τ of the SLR to the average length of time between the formations of AGB progenitors γ, we calculate timescales relevant for the birth of the Sun. If τ/γ ≳ 2, we predict self-consistent isolation times between 9 and 26 Myr by decaying the GCE predicted 107Pd/108Pd, 135Cs/133Cs, and 182Hf/180Hf ratios to their respective ESS ratios. The predicted 107Pd/182Hf ratio indicates that our GCE models are missing 9%–73% of 107Pd and 108Pd in the ESS. This missing component may have come from AGB stars of higher metallicity than those that contributed to the ESS in our GCE code. If τ/γ ≲ 0.3, we calculate instead the time (T LE) from the last nucleosynthesis event that added the SLRs into the presolar matter to the formation of the oldest solids in the ESS. For the 2 M ⊙, Z = 0.01 Monash model we find a self-consistent solution of T LE = 25.5 Myr.

Stellar Parameters, Chemical composition and Models of chemical evolution

2017 ◽  
Vol 12 (S330) ◽  
pp. 331-332
Author(s):  
T. Mishenina ◽  
M. Pignatari ◽  
B. Côté ◽  
F.-K. Thielemann ◽  
C. Soubiran ◽  
...  
Keyword(s):  
Chemical Composition ◽  
High Resolution ◽  
Chemical Evolution ◽  
Stellar Nucleosynthesis ◽  
Depth Study ◽  
Astrometric Data

AbstractWe present an in-depth study of metal-poor stars, based high resolution spectra combined with newly released astrometric data from Gaia, with special attention to observational uncertainties. The results are compared to those of other studies, including Gaia benchmark stars. Chemical evolution models are discussed, highlighting few puzzles that are still affecting our understanding of stellar nucleosynthesis and of the evolution of our Galaxy.

scholarly journals The Early History of Our Galaxy: Chemical Evolution

1974 ◽  
Vol 58 ◽  
pp. 141-156
Author(s):  
Manuel Peimbert
Keyword(s):  
Chemical Evolution ◽  
Stellar Evolution ◽  
Local Group ◽  
Early History ◽  
The Other ◽  
Heavy Elements ◽  
Galactic Chemical Evolution ◽  
Chemical Abundance ◽  
Iron Abundance ◽  
History Of

A general review is given of chemical abundance determinations; particular emphasis is given to abundances of galactic and extragalactic metal-poor objects since presumably they represent the abundances of the primeval material from which our Galaxy was formed. The following results are stressed: (a) most of the helium present in the galaxies of the local group as well as in other galaxies was produced before these objects were formed, (b) the heavy elements were produced mainly as the result of stellar evolution, (c) there is a chemical abundance gradient in our Galaxy and, by analogy with other galaxies, it is expected to be steeper near the nucleus, (d) the carbon and oxygen content of our Galaxy increased at a rate different from the metals, reaching their present abundance earlier than the other heavy elements, and (e) the increase of the iron abundance in the disk of our Galaxy with time has been small while that of carbon is negligible; furthermore, as a group the super-metal-rich stars correspond to the old disk population. Several models of galactic chemical evolution are reviewed.

scholarly journals Mitochondrial function and aerobic capacity assessed by high resolution respirometry in Thoroughbred horses

2016 ◽  
Vol 12 (2) ◽  
pp. 67-73 ◽  
Author(s):  
D. Serteyn ◽  
J. Ceusters ◽  
S. Nonnenmacher ◽  
K. Kirsch ◽  
A. Mouithys-Mickalad ◽  
...  
Keyword(s):  
High Resolution ◽  
Aerobic Capacity ◽  
Mitochondrial Function ◽  
Complex I ◽  
Oxygen Flux ◽  
Training Period ◽  
Mean Values ◽  
Thoroughbred Horses ◽  
Before And After ◽  
The Mean

During the initial stages of training of young Thoroughbred horses, low intensity exercise is employed to increase aerobic capacity. High Resolution Respirometry (HRR) allows the determination of aerobic capacities in small samples of permeabilised muscle fibres. The aim of the study was to measure the mitochondrial function by HRR in Thoroughbred horses, to compare these values to Warmblood horses and to evaluate the effect of a 10-weeks training period. The mitochondrial function was measured by HRR using different substrate-uncoupler protocols (SUIT 1 and 2) in muscle microbiopsies from two groups of untrained horses: 17 Warmblood and 8 Thoroughbred and in the group of 8 Thoroughbred horses before and after a 10-week training period. The SUIT1 protocol employed to compare the two groups of horses showed that in Thoroughbred horses, the mean values for oxygen flux expressed as tissue mass-specific respiration were significantly higher for complex I (CI)Glutamate+Malate, CI + complex II, and maximum electron transport capacities (ETSmax) than the mean values measured in Warmblood horses. The SUIT 1 and SUIT 2 protocols revealed large differences among Thoroughbred horses before and after training. The SUIT 2 protocols showed a significant difference for the complex I activity before and after training but only when the oxygen flux was expressed as percentage of ETSmax. This study shows the interest of HRR in equine sport medicine and exercise physiology, but shows that the technique requires further refinement. Indeed significant differences have been shown between the Thoroughbred and the Warmblood horses highlighting the need to have baseline data for each breed. The Thoroughbred horses had globally a high oxidative phosphorylation capacity with an increase of CI activity induced by an aerobic training program.

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