Published in Publications of the Astronomical Society of Australia, Volume 31, id.e030
http://arxiv.org/abs/1405.0062

For a PDF version of the article, click here.

THE DAWES REVIEW 2: NUCLEOSYNTHESIS AND STELLAR YIELDS OF LOW- AND INTERMEDIATE-MASS SINGLE STARS

Amanda I. Karakas1 and John C. Lattanzio 2


1 Research School of Astronomy & Astrophysics, Australian National University, Canberra, ACT 2611, Australia
2 Monash Centre for Astrophysics, School of Mathematical Sciences, Monash University, Clayton, VIC 3800, Australia


Abstract: The chemical evolution of the Universe is governed by the chemical yields from stars, which in turn are determined primarily by the initial stellar mass. Even stars as low as 0.9 M can, at low metallicity, contribute to the chemical evolution of elements. Stars less massive than about 10 M experience recurrent mixing events that can significantly change the surface composition of the envelope, with observed enrichments in carbon, nitrogen, fluorine, and heavy elements synthesized by the slow neutron capture process (the s-process). Low- and intermediate-mass stars release their nucleosynthesis products through stellar outflows or winds, in contrast to massive stars that explode as core-collapse supernovae. Here we review the stellar evolution and nucleosynthesis for single stars up to ~ 10 M from the main sequence through to the tip of the asymptotic giant branch (AGB). We include a discussion of the main uncertainties that affect theoretical calculations and review the latest observational data, which are used to constrain uncertain details of the stellar models. We finish with a review of the stellar yields available for stars less massive than about 10 M and discuss efforts by various groups to address these issues and provide homogeneous yields for low- and intermediate-mass stars covering a broad range of metallicities.


Keywords: stars: AGB and post-AGB - nucleosynthesis - ISM: composition - Population II stars - stars: mixing - chemical evolution

The Dawes Reviews are substantial reviews of topical areas in astronomy, published by authors of international standing at the invitation of the PASA Editorial Board. The reviews recognise William Dawes (1762-1836), second lieutenant in the Royal Marines and the astronomer on the First Fleet. Dawes was not only an accomplished astronomer, but spoke five languages, had a keen interest in botany, mineralogy, engineering, cartography and music, compiled the first Aboriginal-English dictionary, and was an outspoken opponent of slavery.


Table of Contents

INTRODUCTION
Definitions and Overview of Evolution
The Lowest Mass Stars
The Low Mass Stars
The Intermediate Mass Stars
The Lower Intermediate Mass Stars
The Middle Intermediate Mass Stars
The Massive Intermediate Mass Stars
The Massive Stars
Stellar Yield Calculations

EVOLUTION AND NUCLEOSYNTHESIS PRIOR TO THE ASYMPTOTIC GIANT BRANCH
Illustrative Examples
First Dredge-Up
Abundance Changes due to FDU
The Onset of FDU
The Bump in the Luminosity Function
The Need for Extra-Mixing
The 3He problem
Non-convective mixing processes on the First Giant Branch
The onset of extra mixing
Rotation
Parameterised models
Thermohaline mixing
Magnetic Fields and Other Mechanisms
Lithium
Second Dredge-Up
Variations at low metallicity
Curtailing First Dredge-Up
The Core Helium Flash
Proton Ingestion Episodes

EVOLUTION AND NUCLEOSYNTHESIS DURING THE ASYMPTOTIC GIANT BRANCH
The thermally-pulsing Asymptotic Giant Branch
Hot bottom burning
Dredge-up, HBB and the Brightest C Stars
The Core-Mass vs Luminosity Relation
Third dredge up
The Dredge-Up Parameter
The Carbon Star Luminosity Function and other Observational Constraints
Nucleosynthesis during Asymptotic Giant Branch Evolution
Nucleosynthesis via thermal pulses
The carbon isotopic ratio: 12C / 13C
Nitrogen isotopic ratios
The Intershell Oxygen Abundance
Fluorine
Other Species in the Intershell
Heavy Magnesium isotopes
Planetary nebulae and post-AGB stars
Nucleosynthesis from Hot Bottom Burning
C, N, and O
Ne, Na, Mg, and Al
Lithium
Type I planetary nebulae
The slow neutron capture process
Neutron sources in AGB stars
The formation of 13C pockets
The s-process in low-mass AGB stars
The s-process in intermediate-mass AGB stars
Proton ingestion episodes: PIEs
Overview of 1D PIEs
1D PIEs and the i-process
Yields from 1D PIEs
Multi-dimensional PIE calculations
Beyond the AGB: Super-AGB stars
Super-AGB Evolution
Third Dredge-Up
Super-AGB Nucleosynthesis
Final fates of AGB and Super-AGB stars

MAJOR UNCERTAINTIES
Convection and the third dredge up
Determining the Borders of Convection
Structural Changes from Convection
Mass loss
Extra mixing in AGB stars
Low temperature Opacities
The s-process
Binary evolution

CHEMICAL ENRICHMENT FROM AGB STARS
Stellar yields from AGB stars
Summary of elements produced by low and intermediate-mass stars
Lithium
Carbon, Nitrogen, Oxygen
Fluorine
From Neon to Iron
Heavy elements produced by the s-process

SUMMARY AND OUTLOOK

REFERENCES

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