| Issue |
A&A
Volume 576, April 2015
|
|
|---|---|---|
| Article Number | A118 | |
| Number of page(s) | 18 | |
| Section | Stellar structure and evolution | |
| DOI | https://doi.org/10.1051/0004-6361/201424739 | |
| Published online | 16 April 2015 | |
Online material
Appendix A: Best-fitting models to the observed CEMP-s stars in our sample
In this section we show the best-fitting models to the observed abundances of all CEMP-s stars in our sample.
 |
Fig. A.1
Points with error bars: as Fig. 4 for BD+ 04°2466. Solid line: best-fitting model computed with model set A (Table 2). The combined abundance of carbon and nitrogen is shown in the right panel. |
| Open with DEXTER | |
 |
Fig. A.2
Star CS22948–027. Solid line and points: as Fig. A.1. In the best model (with model set B) the secondary star accretes ΔMacc = 0.27 M⊙. With model set A (dashed line) the secondary star accretes ΔMacc = 0.12 M⊙ and therefore the material is more strongly diluted. |
| Open with DEXTER | |
 |
Fig. A.3
Solid line and points: as Fig. A.1 for CS22956–028. The best-fitting model assumes that non-convective mixing processes, such as thermohaline mixing, are inefficient and therefore the accreted material remains on the surface of the star. Dashed line: alternative model with efficient thermohaline mixing (χ2 = 51.8). |
| Open with DEXTER | |
 |
Fig. A.4
Points with error bars: as in Fig. A.1 for CS29497–034. Solid line: best-fitting model computed with set B adopting the default metallicity Z = 10-4. |
| Open with DEXTER | |
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Fig. A.5
As Fig. A.1 for CS29509–027. The abundance of other elemens, such as N, Na, Mg and Pb, is necessary to better constrain the initial primary mass. |
| Open with DEXTER | |
 |
Fig. A.6
As Fig. A.1 for HD 198269. The best-fitting model (solid line) is computed adopting model set B. The abundances determined by Van Eck et al. (2003) and Vanture (1992b) are represented as plus signs and filled circles, respectively. |
| Open with DEXTER | |
 |
Fig. A.7
As Fig. A.1 for HD 201626. The best-fitting model to the observed abundances is found with model set B. |
| Open with DEXTER | |
 |
Fig. A.8
As Fig. A.1 for CEMP-s/r star HD 224959. The abundances determined by Van Eck et al. (2003) and Vanture (1992b) are represented as plus signs and filled circles, respectively. |
| Open with DEXTER | |
 |
Fig. A.9
Points with error bars: as Fig. A.1 for HE0024–2523. Solid line: best-fitting model found with model set B and assuming a low efficiency for common-envelope ejection, αCE = 0.03, which is required to reproduce the observed period of Porb = 3.14 days in a binary scenario. Dashed line: alternative scenario in which the HE0024–2523 was initially part of a hierarchical triple system. An intermediate-mass primary star was in a wide orbit around a close binary. During its AGB phase the primary star pollutes the inner binary. Subsequently, the secondary star overfills its Roche lobe, the system enters a common envelope the ejection of which (modelled with αCE = 1.0) requires the orbit to shrink to the observed period. |
| Open with DEXTER | |
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Fig. A.10
As Fig. A.1 for star HE0507–1430. The best-fit model is found with model set B. |
| Open with DEXTER | |
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Fig. A.11
As in Fig. A.1 for star LP625–44. The best-fit model is found with model set B. |
| Open with DEXTER | |
Appendix B: Two-dimensional confidence intervals
Figure B.1a shows the two-dimensional confidence regions determined for the initial orbital period, Pi, and primary mass, M1,i, of model star CS29497–034. The one-dimensional confidence intervals of these two parameters are shown in Figs. B.1b and c, respectively, in which the same symbols as in Fig. 5 are used. Figure B.2 is the same as Fig. B.1 for star HD 201626. To compute the two-dimensional confidence intervals of two input parameters p and p′ we follow the same procedure as described in Sect. 4.3, but we fix a pair of values (p,p′) and we let the other two parameters vary. In two dimensions the confidence levels of 68.3%,95.4% and 99.7% correspond respectively to the thresholds Δχ2 = 2.30, 6.17, 11.8 (Press et al. 1989). These thresholds are shown in Figs. B.1a and B.2a as solid, dashed and dotted lines, respectively.
The two-dimensional confidence intervals in Fig. B.1a indicate that there is correlation between the initial orbital period and primary mass of the model systems. The more massive the primary star is, the longer needs to be the initial period to minimise χ2. In Fig. B.2a the correlation between the two parameters in the models of star HD 201626 is even more clear. This correlation indicates that although the confidence range of M1,i is rather large, as shown in Table 4, for each primary mass in our grid there is essentially only one orbital period at which the model reproduces the observations.
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Fig. B.1
Confidence intervals of the input parameters for model star CS29497–034. Panels b) and c): one-dimensional confidence intervals of Pi and M1,i, respectively. Long-dashed lines indicate the thresholds Δχ2 = 1, 4, 9. Panel a): two-dimensional confidence intervals. The thresholds Δχ2 = 2.30, 6.17, 11.8 are represented as solid, dashed and dotted lines, respectively. The blue plus sign indicates the best model. |
| Open with DEXTER | |
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Fig. B.2
Confidence intervals of the input parameters for model star HD 201626. The symbols are as in Fig. B.1. |
| Open with DEXTER | |
© ESO, 2015
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