scholarly journals High-resolution spectroscopy of globular cluster post-Asymptotic Giant Branch stars

2004 ◽  
Vol 419 (3) ◽  
pp. 1123-1132 ◽  
Author(s):  
C. J. Mooney ◽  
W. R. J. Rolleston ◽  
F. P. Keenan ◽  
P. L. Dufton ◽  
J. V. Smoker ◽  
...  
Keyword(s):  
High Resolution ◽  
Globular Cluster ◽  
Asymptotic Giant Branch ◽  
High Resolution Spectroscopy ◽  
Asymptotic Giant Branch Stars ◽  
Giant Branch Stars

scholarly journals High-resolution Keck I spectroscopy of Galactic halo post-asymptotic giant branch stars

2002 ◽  
Vol 337 (3) ◽  
pp. 851-860 ◽  
Author(s):  
C. J. Mooney ◽  
W. R. J. Rolleston ◽  
F. P. Keenan ◽  
P. L. Dufton ◽  
J. V. Smoker ◽  
...  
Keyword(s):  
High Resolution ◽  
Galactic Halo ◽  
Asymptotic Giant Branch ◽  
Asymptotic Giant Branch Stars ◽  
Giant Branch Stars

scholarly journals High Resolution Radio and IR Observations of AGB Stars

2012 ◽  
Vol 8 (S287) ◽  
pp. 245-249
Author(s):  
W. Cotton ◽  
G. Perrin ◽  
R. Millan-Gabet ◽  
O. Delaa ◽  
B. Mennesson
Keyword(s):  
High Resolution ◽  
Molecular Layer ◽  
Asymptotic Giant Branch ◽  
Red Giants ◽  
Asymptotic Giant Branch Stars ◽  
Agb Stars ◽  
Near Ir ◽  
The Subject ◽  
Infrared Interferometry ◽  
Giant Branch Stars

AbstractAsymptotic Giant Branch Stars (AGB) are evolved, mass losing red giants with tenuous molecular envelopes which have been the subject of much recent study using infrared and radio interferometers. In oxygen rich stars, radio SiO masers form in the outer regions of the molecular envelopes and are powerful diagnostics of the extent of these envelopes. Spectroscopically resolved infrared interferometry helps constrain the extent of various species in the molecular layer. We made VLBA 7 mm SiO maser, Keck Interferometer near IR and VLTI/MIDI mid IR high resolution observations of the stars U Ari, W Cnc, RX Tau, RT Aql, S Ser and V Mon. This paper presents evidence that the SiO is depleted from the gas phase and speculate that it is frozen onto Al2O3 grains and that radiation pressure on these grains help drive the outflow.

The role of asymptotic giant branch stars in the chemical evolution of the Galaxy

2018 ◽  
Vol 14 (S343) ◽  
pp. 510-511
Author(s):  
G. Tautvaišienė ◽  
C. Viscasillas Vázquez ◽  
V. Bagdonas ◽  
R. Smiljanic ◽  
A. Drazdauskas ◽  
...  
Keyword(s):  
High Resolution ◽  
Neutron Capture ◽  
Open Clusters ◽  
Asymptotic Giant Branch ◽  
Asymptotic Giant Branch Stars ◽  
Galactic Disc ◽  
The Galaxy ◽  
Process Elements ◽  
Giant Branch Stars

AbstractAsymptotic giant branch stars play an important role in enriching galaxies by s-process elements. Recent studies have shown that their role in producing s-process elements in the Galactic disc was underestimated and should be reconsidered. Based on high-resolution spectra we have determined abundances of neutron-capture elements in a sample of 310 stars located in the field and open clusters and investigated elemental enrichment patterns according to their age and mean galactocentric distances.

scholarly journals Globular cluster abundances: the role of asymptotic giant branch stars

2009 ◽  
Vol 5 (S266) ◽  
pp. 161-168
Author(s):  
Amanda I. Karakas
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
Asymptotic Giant Branch ◽  
Asymptotic Giant Branch Stars ◽  
Agb Stars ◽  
Modelling Uncertainties ◽  
Low Metallicity ◽  
Abundance Anomalies ◽  
Giant Branch Stars

AbstractOne of the more popular theories to account for the abundance anomalies in globular cluster stars is the ‘self-pollution scenario,’ where the polluters were a previous generation of intermediate-mass asymptotic giant branch (AGB) stars. This idea has proved attractive because: (i) the hot-bottom burning experienced by these objects qualitatively provides an ideal proton-capture environment to produce helium and convert C and O to N, Ne to Na and Mg to Al, and (ii) the slow winds from these stars allow their retention by the cluster's gravitational potential. New stellar yields from low-metallicity AGB models are presented and compared to abundances derived in globular clusters. We also discuss external pollution and inhomogeneous-pollution models that use AGB stars as polluters. Current models of AGB stars cannot match all observational features of globular cluster stars. However, stellar modelling uncertainties are considerable and suggest AGB stars should not be ruled out just yet.

scholarly journals Production of Aluminium and the Heavy Magnesium Isotopes in Asymptotic Giant Branch Stars

2003 ◽  
Vol 20 (3) ◽  
pp. 279-293 ◽  
Author(s):  
A. I. Karakas ◽  
J. C. Lattanzio
Keyword(s):  
Globular Cluster ◽  
Main Sequence ◽  
Stellar Mass ◽  
Asymptotic Giant Branch ◽  
Asymptotic Giant Branch Stars ◽  
Magnesium Isotopes ◽  
Wide Range ◽  
Abundance Anomalies ◽  
Stellar Models ◽  
Giant Branch Stars

AbstractWe investigate the production of aluminium and magnesium in asymptotic giant branch models covering a wide range in mass and composition. We evolve models from the pre-main sequence, through all intermediate stages, to near the end of the thermally-pulsing asymptotic giant branch phase. We then perform detailed nucleosynthesis calculations from which we determine the production of the magnesium and aluminium isotopes as a function of the stellar mass and composition. We present the stellar yields of sodium and the magnesium and aluminium isotopes. We discuss the abundance predictions from the stellar models in reference to abundance anomalies observed in globular cluster stars.

scholarly journals The pollution of the interstellar medium from AGB stars in Globular Clusters

2012 ◽  
Vol 10 (H16) ◽  
pp. 249-250
Author(s):  
Paolo Ventura ◽  
Roberta Carini
Keyword(s):  
Globular Cluster ◽  
Globular Clusters ◽  
The Self ◽  
Asymptotic Giant Branch ◽  
Asymptotic Giant Branch Stars ◽  
Agb Stars ◽  
Initial Value ◽  
Low Metallicity ◽  
Giant Branch Stars ◽  
High Metallicity

AbstractWe discuss the yields from Asymptotic Giant Branch stars, depending on their mass and metallicity. In agreement with previous investigations, we find that the extent of Hot Bottom Burning increases with mass. The yields of models with chemistry typical of high–metallicity Globular Clusters, i.e. Z = 0.008, show only a modest depletion of magnesium, and an oxgen depletion of ~ 0.4 dex. Low–metallicity yields show a much stronger magnesium depletion, and a dramatic drop in the oxygen content, ~ 1.2dex smaller than the initial value. We suggest that the Globular Cluster NGC 2419 is a possible target to the hypothesis of the self–enrichment scenario of Globular Clusters by the winds of Asymptotic Giant Branch stars.

Observations of High Rotational CO Lines in Post–Asymptotic Giant Branch Stars and Planetary Nebulae

1997 ◽  
Vol 476 (1) ◽  
pp. 319-326 ◽  
Author(s):  
K. Justtanont ◽  
A. G. G. M. Tielens ◽  
C. J. Skinner ◽  
Michael R. Haas
Keyword(s):  
Planetary Nebulae ◽  
Asymptotic Giant Branch ◽  
Asymptotic Giant Branch Stars ◽  
Giant Branch Stars

scholarly journals Carbon stars as standard candles – II. The median J magnitude as a distance indicator

2020 ◽  
Vol 501 (1) ◽  
pp. 933-947
Author(s):  
Javiera Parada ◽  
Jeremy Heyl ◽  
Harvey Richer ◽  
Paul Ripoche ◽  
Laurie Rousseau-Nepton
Keyword(s):  
Luminosity Function ◽  
Asymptotic Giant Branch ◽  
Distance Modulus ◽  
Asymptotic Giant Branch Stars ◽  
Luminosity Functions ◽  
Best Fitting ◽  
Distance Indicator ◽  
Ngc 6822 ◽  
The Given ◽  
Giant Branch Stars

ABSTRACT We introduce a new distance determination method using carbon-rich asymptotic giant branch stars (CS) as standard candles and the Large and Small Magellanic Clouds (LMC and SMC) as the fundamental calibrators. We select the samples of CS from the ((J − Ks)0, J0) colour–magnitude diagrams, as, in this combination of filters, CS are bright and easy to identify. We fit the CS J-band luminosity functions using a Lorentzian distribution modified to allow the distribution to be asymmetric. We use the parameters of the best-fitting distribution to determine if the CS luminosity function of a given galaxy resembles that of the LMC or SMC. Based on this resemblance, we use either the LMC or SMC as the calibrator and estimate the distance to the given galaxy using the median J magnitude ($\overline{J}$) of the CS samples. We apply this new method to the two Local Group galaxies NGC 6822 and IC 1613. We find that NGC 6822 has an ‘LMC-like’ CS luminosity function, while IC 1613 is more ‘SMC-like’. Using the values for the median absolute J magnitude for the LMC and SMC found in Paper I we find a distance modulus of μ0 = 23.54 ± 0.03 (stat) for NGC 6822 and μ0 = 24.34 ± 0.05 (stat) for IC 1613.

Finite Temperature Behavior of Carbon Atom Doped Silicon Clusters: Depressed Thermal Stabilities, Co-existing isomers, Reversible Dynamical Pathways and Fragmentation Channels

2021 ◽  
Author(s):  
Krati Joshi ◽  
Ashakiran Maibam ◽  
Sailaja Krishnamurty
Keyword(s):  
Silicon Carbide ◽  
Carbon Atom ◽  
Finite Temperature ◽  
Asymptotic Giant Branch ◽  
Temperature Behavior ◽  
Asymptotic Giant Branch Stars ◽  
Silicon Clusters ◽  
Thermal Stabilities ◽  
Doped Silicon ◽  
Giant Branch Stars

Silicon carbide clusters are significant due to their predominant occurrence in meteoric star dust, particularly in carbon rich asymptotic giant branch stars. Of late, they have also been recognized as...

Sign in / Sign up

Export Citation Format

Share Document