# Carbon and oxygen isotopic ratios in Arcturus and Aldebaran - Constraining the parameters for non-convective mixing on the red giant branch

@article{Abia2012CarbonAO,
title={Carbon and oxygen isotopic ratios in Arcturus and Aldebaran - Constraining the parameters for non-convective mixing on the red giant branch},
author={Carlos Abia and Sara Palmerini and Maurizio Busso and Sergio Cristallo},
journal={Astronomy and Astrophysics},
year={2012},
volume={548}
}
• Published 3 October 2012
• Physics, Environmental Science
• Astronomy and Astrophysics
Context. We re-analyzed the carbon and oxygen isotopic ratios in the atmospheres of the two bright K giants Arcturus (α Boo) and Aldebaran (α Tau). Aims. These stars are in the evolutionary stage following the first dredge-up (FDU). Previous determinations (dating back more than 20 years) of their 16 O/ 18 O ratios showed a rough agreement with FDU expectations; however, the estimated 16 O/ 17 Oa nd 12 C/ 13 Cr atios were lower than in the canonical predictions for red giants. Today these…

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## References

SHOWING 1-10 OF 65 REFERENCES

### Cool Bottom Processes on the Thermally Pulsing Asymptotic Giant Branch and the Isotopic Composition of Circumstellar Dust Grains

• Physics
• 2002
We examine the effects of cool bottom processing (CBP) on the isotopic ratios 18O/16O, 17O/16O, 14N/15N, 26Al/27Al, C/O, and N/O in the convective envelope during the thermally pulsing asymptotic

### THERMOHALINE MIXING AND ITS ROLE IN THE EVOLUTION OF CARBON AND NITROGEN ABUNDANCES IN GLOBULAR CLUSTER RED GIANTS: THE TEST CASE OF MESSIER 3

• Physics
• 2011
We review the observational evidence for extra mixing in stars on the red giant branch (RGB) and discuss why thermohaline mixing is a strong candidate mechanism. We recall the simple phenomenological

### Deep Circulation in Red Giant Stars: A Solution to the Carbon and Oxygen Isotope Puzzles?

• Physics
• 1995
The long-standing puzzle of low 12C/13C in low-mass red giant branch (RGB) stars, and the more recent puzzle of low 18O/16O ratios in asymptotic giant branch (AGB) stars and in circumstellar Al2O3

### Thermohaline instability and rotation-induced mixing I. Low- and intermediate-mass solar metallicity stars up to the end of the AGB

• Physics
• 2010
Context. Numerous spectroscopic observations provide compelling evidence for non-canonical processes that modify the surface abundances of low- and intermediate-mass stars beyond the predictions of

### Thermohaline mixing: a physical mechanism governing the photospheric composition of low-mass giants

Aims. Numerous spectroscopic observations provide compelling evidence for a non-canonical mixing process that modifies the surface abundances of Li, C and N of low-mass red giants when they reach the

### FUNDAMENTAL PARAMETERS AND CHEMICAL COMPOSITION OF ARCTURUS

• Physics
• 2011
We derive a self-consistent set of atmospheric parameters and abundances of 17 elements for the red giant star Arcturus: Teff = 4286 ± 30 K, log g = 1.66 ± 0.05, and [Fe/H] = −0.52 ± 0.04. The

### The abundances of the elements in the solar photosphere – VIII. Revised abundances of carbon, nitrogen and oxygen

All accessible atomic and molecular signatures of carbon, nitrogen and oxygen are integrated in this comprehensive updating of an earlier paper in this series (Lambert 1968). The reasons for

### Magnetic Mixing in Red Giant and Asymptotic Giant Branch Stars

• Physics
• 2008
The available information on isotopic abundances in the atmospheres of low-mass red giant branch (RGB) and asymptotic giant branch (AGB) stars requires that episodes of extensive mixing occur below

### EVOLUTION, NUCLEOSYNTHESIS, AND YIELDS OF LOW-MASS ASYMPTOTIC GIANT BRANCH STARS AT DIFFERENT METALLICITIES

• Physics
• 2009
The envelope of thermally pulsing asymptotic giant branch (TP-AGB) stars undergoing periodic third dredge-up (TDU) episodes is enriched in both light and heavy elements, the ashes of a complex

### DEEP MIXING IN EVOLVED STARS. I. THE EFFECT OF REACTION RATE REVISIONS FROM C TO Al

• Physics
• 2011
We present computations of nucleosynthesis in low-mass (LM) red giant branch (RGB) and asymptotic giant branch (AGB) stars of Population I experiencing extended mixing. We adopt the updated version