Search Results - "Karakas, A I"

Updated stellar yields from asymptotic giant branch models by Karakas, A. I.

“…An updated grid of stellar yields for low- to intermediate-mass thermally pulsing asymptotic giant branch (AGB) stars is presented. The models cover a range in…”
Get full text

On the formation of neutron stars via accretion-induced collapse in binaries by Ruiter, A J, Ferrario, L, Belczynski, K, Seitenzahl, I R, Crocker, R M, Karakas, A I

Get full text

The chemical compositions of solar twins in the open cluster M67 by Liu, F., Asplund, M., Yong, D., Meléndez, J., Ramírez, I., Karakas, A. I., Carlos, M., Marino, A. F.

“…Stars in open clusters are expected to share an identical abundance pattern. Establishing the level of chemical homogeneity in a given open cluster deserves…”
Get full text

The Large Magellanic Cloud as a laboratory for hot bottom burning in massive asymptotic giant branch stars by Ventura, P., Karakas, A. I., Dell'Agli, F., Boyer, M. L., García-Hernández, D. A., Di Criscienzo, M., Schneider, R.

“…We use Spitzer observations of the rich population of asymptotic giant branch (AGB) stars in the Large Magellanic Cloud (LMC) to test models describing the…”
Get full text

Two distinct sequences of blue straggler stars in the globular cluster M 30 by Lanzoni, B, Karakas, A. I, Ferraro, F. R, Bovinelli, S, Miocchi, P, Beccari, G, Dalessandro, E, Rood, R. T, Sills, A, Pecci, F. Fusi

“…Stars in globular clusters are generally believed to have all formed at the same time, early in the Galaxy's history. 'Blue stragglers' are stars massive…”
Get full text

EVOLUTION AND NUCLEOSYNTHESIS OF ASYMPTOTIC GIANT BRANCH STARS IN THREE MAGELLANIC CLOUD CLUSTERS by KAMATH, D, KARAKAS, A. I, WOOD, P. R

“…We present stellar evolutionary sequences for asymptotic giant branch (AGB) stars in the Magellanic Cloud clusters NGC 1978, NGC 1846, and NGC 419. The new…”
Get full text

On the nature of the most obscured C-rich AGB stars in the Magellanic Clouds by Ventura, P., Karakas, A. I., Dell'Agli, F., García–Hernández, D. A., Boyer, M. L., Di Criscienzo, M.

“…The stars in the Magellanic Clouds with the largest degree of obscuration are used to probe the highly uncertain physics of stars in the asymptotic giant…”
Get full text

Double white dwarf mergers and elemental surface abundances in extreme helium and RCoronaeBorealis stars by Jeffery, C S, Karakas, AI, Saio, H

“…ABSTRACT The surface abundances of extreme helium (EHe) and RCoronaeBorealis (RCB) stars are discussed in terms of a model for their origin in the merger of a…”
Get full text

The effect of including molecular opacities of variable composition on the evolution of intermediate-mass AGB stars by Fishlock, C. K., Karakas, A. I., Stancliffe, R. J.

“…Calculations from stellar evolutionary models of low- and intermediate-mass asymptotic giant branch (AGB) stars provide predictions of elemental abundances and…”
Get full text

The chemical evolution of globular clusters – I. Reactive elements and non-metals by Marcolini, A., Gibson, B. K., Karakas, A. I., Sánchez-Blázquez, P.

“…We propose a new chemical evolution model aimed at explaining the chemical properties of globular clusters (GCs) stars. Our model depends upon the existence of…”
Get full text

Rb-Rich Asymptotic Giant Branch Stars in the Magellanic Clouds by García-Hernández, D. A, Manchado, A, Lambert, D. L, Plez, B, García-Lario, P, D'Antona, F, Lugaro, M, Karakas, A. I, van Raai, M. A

“…We present high-resolution (R approx 60,000) optical spectra of a carefully selected sample of heavily obscured and presumably massive O-rich asymptotic giant…”
Get full text

SALT reveals the barium central star of the planetary nebula Hen 2-39 by Miszalski, B., Boffin, H. M. J., Jones, D., Karakas, A. I., Köppen, J., Tyndall, A. A., Mohamed, S. S., Rodríguez-Gil, P., Santander-García, M.

“…Classical barium stars are binary systems which consist of a late-type giant enriched in carbon and slow neutron capture (s-process) elements and an evolved…”
Get full text

Modelling self-pollution of globular clusters from asymptotic giant branch stars by Fenner, Y., Campbell, S., Karakas, A. I., Lattanzio, J. C., Gibson, B. K.

“…Abstract A self-consistent model of the chemical evolution of the globular cluster NGC 6752 is presented to test a popular theory that observed abundance…”
Get full text

The Chemical Evolution of Helium in Globular Clusters: Implications for the Self-Pollution Scenario by Karakas, A. I, Fenner, Y, Sills, Alison, Campbell, S. W, Lattanzio, J. C

“…We investigate the suggestion that there are stellar populations in some globular clusters with enhanced helium (Y 6 0.28-0.40) compared to the primordial…”
Get full text

The 95Zr(n, γ)96Zr Cross Section from the Surrogate Ratio Method and Its Effect on s-process Nucleosynthesis by Yan, S. Q., Li, Z. H., Wang, Y. B., Nishio, K., Lugaro, M., Karakas, A. I., Makii, H., Mohr, P., Su, J., Li, Y. J., Nishinaka, I., Hirose, K., Han, Y. L., Orlandi, R., Shen, Y. P., Guo, B., Zeng, S., Lian, G., Chen, Y. S., Liu, W. P.

“…The 95Zr(n, γ)96Zr reaction cross section is crucial in the modeling of s-process nucleosynthesis in asymptotic giant branch stars because it controls the…”
Get full text

Iron and s-elements abundance variations in NGC 5286: comparison with ‘anomalous' globular clusters and Milky Way satellites by Marino, A. F., Milone, A. P., Karakas, A. I., Casagrande, L., Yong, D., Shingles, L., Da Costa, G., Norris, J. E., Stetson, P. B., Lind, K., Asplund, M., Collet, R., Jerjen, H., Sbordone, L., Aparicio, A., Cassisi, S.

“…We present a high-resolution spectroscopic analysis of 62 red giants in the Milky Way globular cluster (GC) NGC 5286. We have determined abundances of…”
Get full text

Heavy elements in barium stars by Roriz, M P, Lugaro, M, Pereira, C B, Sneden, C, Junqueira, S, Karakas, A I, Drake, N A

“…ABSTRACT New elemental abundances for the neutron-capture elements Sr, Nb, Mo, Ru, La, Sm, and Eu are presented for a large sample of 180 barium (Ba) giant…”
Get full text

ON POTASSIUM AND OTHER ABUNDANCE ANOMALIES OF RED GIANTS IN NGC 2419 by Iliadis, C., Karakas, A. I., Prantzos, N., Lattanzio, J. C., Doherty, C. L.

“…ABSTRACT Globular clusters are of paramount importance for testing theories of stellar evolution and early galaxy formation. Strong evidence for multiple…”
Get full text

Modelling of the post-asymptotic giant branch phase as a tool to understand asymptotic giant branch evolution and nucleosynthesis by Kamath, D, Dell’Agli, F, Ventura, P, Van Winckel, H, Tosi, S, Karakas, A I

“…ABSTRACT We study a sample of single Galactic post-asymptotic giant branch (post-AGB) stars with known surface chemical composition. Gaia  EDR3 and Gaia  DR3…”
Get full text

The complex stellar system M 22: confirming abundance variations with high precision differential measurements by McKenzie, M, Yong, D, Marino, A F, Monty, S, Wang, E, Karakas, A I, Milone, A P, Legnardi, M V, Roederer, I U, Martell, S, Horta, D

“…ABSTRACT M 22 (NGC 6656) is a chemically complex globular cluster-like system reported to harbour heavy element abundance variations. However, the extent of…”
Get full text