Uncertainties and Systematics in Stellar Evolution Models of Red Giant Stars

Cassisi, S.

doi:10.1007/978-3-642-18418-5_6

Cited by 7 publications

(5 citation statements)

References 82 publications

(152 reference statements)

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“…Meissner & Weiss [18] showed that (for their models) the bump location of GC-type isochrones was inconsistent with the TO brightness for any given age. The fact that the bump tends to be too bright by about 0.2 mag was confirmed, among others, by [13], in particular for the lowest metallicities.…”

Section: The Location Of the Bumpmentioning

confidence: 60%

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Low-mass stars: Open problems all along their evolution

Weiß

Heners

2013

EPJ Web of Conferences

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Abstract. Although low-mass stars have a comparatively simple structure, current stellar models are far from reproducing them accurately. In light of the observational progress, in particular of asteroseismology, the deficits of the theory of stellar structure and evolution become increasingly evident, and can no longer be hidden under the carpet of observational errors. In my brief review I will discuss a number of obvious problems of the models, which are mainly -and not surprisingly so -connected with convective and other mixing processes. They begin already on the pre-main sequence and continue throughout the complete evolution. In addition to the deficits in the treatment of physical processes I will also address our difficulties in obtaining completely satisfying agreement between different numerical codes. It will be shown that this concerns already the main sequence evolution of low-mass stars without a convective core. Keeping this in mind, it is no surprise that models for stars on the Asymptotic Giant Branch differ widely.

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Section: The Location Of the Bumpmentioning

confidence: 60%

“…On the other hand, "several times the typical value" for overshooting from the bottom of the convective envelope is needed for an efficient 13 C neutron source [27], and generally, in 3d-hydro simulations a variation by a factor of 10 is found [28].…”

Section: The Asymptotic Giant Branch Phasementioning

confidence: 99%

Low-mass stars: Open problems all along their evolution

Weiß

Heners

2013

EPJ Web of Conferences

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“…However, the significant improvements of the last decade regarding stellar physics inputs (see Cassisi 2005Cassisi , 2009Cassisi , 2010Cassisi , 2012, and references therein) require an updated theoretical framework for these populations. A&A 558, A46 (2013) At the other extreme of the metallicity spectrum, both spectroscopic and photometric surveys (see Gonzalez et al 2011, and references therein) show that the Galactic bulge metallicity distribution (peaked at about solar metallicity) displays an extended tail reaching [Fe/H] ∼ +1.0.…”

Section: Introductionmentioning

confidence: 99%

The BaSTI Stellar Evolution Database: models for extremely metal-poor and super-metal-rich stellar populations

Pietrinferni

Cassisi

Salaris

et al. 2013

A&A

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We present an extension of the BaSTI (Bag of Stellar Tracks and Isochrones) stellar evolution database to extremely metal-poor (Z = 10 −5 ) and super-metal-rich (Z = 0.05) metallicities, with both scaled-solar and α-enhanced ([α/Fe] = 0.4) heavy element distributions. These new tracks (from the pre-main sequence to the early-asymptotic giant branch phase), horizontal branch models, and isochrones will enable the use of the BaSTI database to study the most metal-poor populations found in Local Group faint dwarf galaxies, and the metal-rich component of the Galactic bulge, for example. An overview of several fundamental predictions of stellar evolution over the full metallicity range of BaSTI is presented, together with comparisons with literature calculations at Z = 10 −5 and Z = 0.05.

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“…Even more important, however, is the fact that we have used the position of the RGB bump as a reference point in our analysis. Unfortunately, the predicted RGB bump position is known to be affected by ill-constrained physical processes, and is thus subject to large systematic errors (e.g., [3], and references therein). Such errors were not taken into account in the present study.…”

Section: −12mentioning

confidence: 99%

“…This way, we obtain evolutionary tracks for 02004-p. 3 Based on the computed tracks, we then evaluate the theoretically expected TRGB and RGB bump I -band magnitudes, and finally derive the predicted dependence of I TRGB Bump on ν . This is shown as filled circles in Figure 5.…”

Section: Theoretical Frameworkmentioning

confidence: 99%

The galactic globular cluster M5 (NGC 5904) as a particle physics laboratory

Viaux

Catelan

Raffelt

et al. 2013

EPJ Web of Conferences

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Abstract. Globular clusters have been used for a long time to test stellar evolution theories, and in particular to constrain novel forms of energy loss in low-mass stars. This includes constraints on axion properties, neutrino dipole moments, milli-charged particles, Kaluza-Klein gravitons, and many other phenomena. Depending on their interaction strength, these particles can be abundantly produced in stellar interiors, escape without further interaction, and thus drain energy directly from the stellar interior. Hence, they contribute directly to the stellar energy losses, thus modifying stellar evolution. Our goal is to re-examine such constraints in the light of modern data and updated stellar evolution codes, paying particular attention to systematic and statistical errors. As a first example, we consider the case of a neutrino magnetic moment that enhances the energy loss from the plasma process.In terms of the observed color-magnitude diagrams, the tip of the red giant branch (RGB) has been identified as a sensitive observable of the effects of the energy losses due to a neutrino magnetic moment. Here we describe the consequences of adding the cooling effect due to a neutrino magnetic moment to the Princeton-Goddard-PUC (PGPUC) stellar evolution code, exploring in particular the dependence of the position of the RGB tip on the neutrino magnetic moment.As a first application, we studied the position of the observed RGB tip in the case of the Galactic globular cluster M5 (NGC 5904), using the latest, high-precision, ground-based data from the P. B. Stetson database (2012, priv. comm.). We compare the empirical results with the PGPUC model predictions, and discuss the implied constraints on the value of the neutrino magnetic moment.

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Uncertainties and Systematics in Stellar Evolution Models of Red Giant Stars

Cited by 7 publications

References 82 publications

Low-mass stars: Open problems all along their evolution

Low-mass stars: Open problems all along their evolution

The BaSTI Stellar Evolution Database: models for extremely metal-poor and super-metal-rich stellar populations

The galactic globular cluster M5 (NGC 5904) as a particle physics laboratory

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