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

By C. Charbonnel, N. Lagarde. 2010

212 citations recorded by the source corpus.

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 standard stellar theory. Aims. We study the effects of thermohaline instability and rotation-induced mixing in the 1-4 Mrange at solar metallicity. Methods. We present evolutionary models by considering both thermohaline and rotation-induced mixing in stellar interior. We discuss the effects of these processes on the chemical properties of stars from the zero age main sequence up to the end of the second dredge-up on the early-AGB for intermediate-mass stars and up to the AGB tip for low-mass stars. Model predictions are compared to observational data for lithium, 12 C/ 13 C, (N/C), (Na/Fe), 16 O/ 17 O, and 16 O/ 18 O in Galactic open clusters and in field stars with well-defined evolutionary status, as well as in planetary nebulae. Results. Thermohaline mixing simultaneously accounts for the observed behaviour of 12 C/ 13 C, (N/C), and lithium in low-mass stars that are more luminous than the RGB bump, and its efficiency is increasing with decreasing initial stellar mass. On the TP-AGB, thermohaline mixing leads to lithium production, although the 7 Li yields remain negative. Although the 3 He stellar yields are much reduced thanks to this process, we find that solar-metallicity, low-mass stars remain net 3 He producers. Rotation-induced mixing is found to change the stellar structure so that in the mass range between ∼1.5 and 2.2 Mthe thermohaline instability occurs earlier on the red giant branch than in non-rotating models. Finally rotation accounts for the observed star-to-star abundance variations at a given evolutionary status, and is necessary to explain the features of CN-processed material in intermediate-mass stars. Conclusions. Overall, the present models account for the observational constraints very well over the whole mass range presently investigated.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/bd36d44343115a69f2e9a170f4bce9211df78710

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

Citations in the corpus

MESA ISOCHRONES AND STELLAR TRACKS (MIST). I. SOLAR-SCALED MODELS (2016, background): “…ignition in semi-degenerate cores (Siess 2009), or the 3He(3He,2p)4He reaction taking place just beyond the hydrogen-burning shell during the RGB, horizontal branch (HB), and AGB (Eggleton et al. 2006; Charbonnel & Zahn 2007; Cantiello & Langer 2010; Charbonnel & Lagarde 2010; Stancliffe 2010).”
Thermohaline instability and rotation-induced mixing - III. Grid of stellar models and asymptotic asteroseismic quantities from the pre-main sequence up to the AGB for low- and intermediate-mass stars of various metallicities (2012, methodology): “– Thermohaline mixing induced by 3He-burning becomes efficient only on the RGB at the bump luminosity (Charbonnel & Zahn 2007b; Charbonnel & Lagarde 2010).”
THE AGE AND MASS OF THE α HERCULIS TRIPLE-STAR SYSTEM FROM A MESA GRID OF ROTATING STARS WITH 1.3 ⩽ M/M☉ ⩽ 8.0 (2013, methodology): “Yet, the choices for the initial rotation rates could be various (compare, e.g. Tassoul 2000; Charbonnel & Lagarde 2010; Cantiello & Langer 2010).”
Improved angular momentum evolution model for solar-like stars II. Exploring the mass dependence (2015, unknown): “…and the redistribution of angular momentum in the stellar interior at all phases of evolution (MacGregor & Brenner 1991; Allain 1998; Talon & Charbonnel 2003, 2005; Palacios et al. 2003, 2006; Charbonnel & Talon 2005; Charbonnel & Lagarde 2010; Lagarde et al. 2011, 2012; Charbonnel et al. 2013).”
The s-Process in Low Metallicity Stars. II. Interpretation of High-Resolution Spectroscopic Observations with AGB models (2011, background): “The resulting efficiency of all these mixing is very difficult to estimate (Vauclair 2004; Eggleton et al. 2006; Charbonnel & Zahn 2007; Charbonnel & Lagarde 2010; Stancliffe & Glebbeek 2008; Stancliffe 2010; Denissenkov & Pinsonneault 2008; Denissenkov et al. 2009; Denissenkov 2010; Cantiello &…”
Red giant masses and ages derived from carbon and nitrogen abundances (2015, unknown): “2 in Charbonnel & Lagarde 2010).”
Chemical tagging with APOGEE: Discovery of a large population of N-rich stars in the inner Galaxy (2016, background): “…000, 2–27 posed involve stellar rotation, thermohaline mixing, magnetic fields, meridional circulation combined with turbulent diffusion, or perhaps some combination of some of these processes (e.g., Renzini & Voli 1981; Charbonnel & Lagarde 2010; Angelou et al. 2012; Karakas & Lattanzio 2014).”