Cumulative physical uncertainty in modern stellar models - II. The dependence on the chemical composition

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Volume 554 (June 2013)

A&A, 554 (2013) A68

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Issue		A&A Volume 554, June 2013


Article Number		A68
Number of page(s)		10
Section		Stellar structure and evolution
DOI		https://doi.org/10.1051/0004-6361/201321142
Published online		05 June 2013

Online material

Table 1

Physical inputs perturbed in the calculations and their assumed uncertainty.

Table 3

Cumulative impact on the uncertainty on isochrone BTO luminosity (dex) and on the mass at isochrone BTO (M_⊙) for different metallicity values.

Table 6

Uncertainty on the age inferred from the BTO luminosity.

Appendix A: On the EOS influence

As discussed in Paper I, the uncertainty on the equation of state (EOS) cannot be treated with the approach applied to the other physical input. To provide a rough estimate of the impact of the present uncertainty on the equation of state, we computed the reference tracks – i.e. the ones with unperturbed physics – with two different and widely adopted choices for: OPAL EOS and FreeEOS (Irwin 2004).

Table A.1

Impact of equation of state change from OPAL to FreeEOS for the examined evolutionary features.

Table A.1 reports – for each evolutionary feature and for each Z – the impact of the EOS change. A comparison of these values with the one of the “Impact” column in Table 2 shows that the EOS change accounts for about 10% to 20% of the total impact of all the other physical input. The only exception is the helium core mass: in this case the impact of the EOS variation accounts for 20% to 40% of the total impact of the other physical input.

Table A.2

Estimated coefficients for the linear model in Eq. (1) of BTO luminosity (dex), for different Z values.

Table A.3

Estimated coefficients for the linear model in Eq. (1) of the central hydrogen exhaustion time (Gyr), for different Z values.

Table A.4

Estimated coefficients for the linear model in Eq. (2) of RGB tip luminosity (dex), for different Z values.

Table A.5

Estimated coefficients for the linear model in Eq. (2) of helium core mass (M_⊙) for different Z values.

Table A.6

Estimated coefficients for the linear model in Eq. (2) of the ZAHB luminosity log L_HB at log T_eff = 3.83 (dex) for different Z values.

Table A.7

Stellar models computed for isochrones construction at different Z values.

© ESO, 2013

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