Astronomy & Astrophysics

All Figures

$\begin{figure} \par\includegraphics[height=7cm,width=7cm,clip]{1528fg1.eps} \end{figure}$ Figure 1: Evolutionary tracks for main sequence models of 1.1 $M_{\odot }$ without accretion (dashed line) and with accretion (full line). The symbols on each track correspond to ages of 30 Myr (asterix), 1 Gyr (diamonds), 4 Gyr (triangles) and 6 Gyr (squares). Here the comparisons are given for two models with the same internal chemical composition. We can see how accretion moves the tracks towards smaller effective temperatures. In the following we will compare models with the same external chemical composition and different internal structure.
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In the text

$\begin{figure} \par\includegraphics[height=7cm,width=7cm,clip]{1528fg2.eps} \end{figure}$ Figure 2: Evolutionary tracks for overmetallic (dashed lines) and accretion (full lines) models. In these computations, the overmetallic models have initial values: Z=0.04 and Y=0.27 while the accretion models have initial values Z=0.02 (increased to 0.04 in the outer layers at the beginning of the main sequence, due to accretion) and Y=0.27. For the overmetallic models, the tracks are plotted, from right to left, for the following masses: 1.1, 1.18, 1.26, and 1.34 $M_{\odot }$ . For the accretion models, the tracks are plotted for 1.0 and 1.1 $M_{\odot }$ .
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In the text

$\begin{figure} \par\includegraphics[height=7cm,width=7cm,clip]{1528fg3.eps} \end{figure}$ Figure 3: Same as Fig. 2, except that here the overmetallic models have initial values: Z=0.04 and Y=0.33.
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In the text

$\begin{figure} \par\includegraphics[height=7cm,width=7cm,clip]{1528fg4.eps} \end{figure}$ Figure 4: Evolutionary tracks for accretion models (full lines) and overmetallic models (dashed lines); in both graphs, the accretion models have a mass of 1.1 $M_{\odot }$ and a solar composition inside (see Table 1); in graph a), the overmetallic models have a mass of 1.3 $M_{\odot }$ and an initial helium mass fraction Y₀=0.27 (solar like); in graph b), the overmetallic models have a mass of 1.15 $M_{\odot }$ and an initial helium mass fraction Y₀=0.33. The crosses identify the models AC1 and OM1 ( a)), and AC2 and OM2 ( b)).
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In the text

$\begin{figure} \par\includegraphics[angle=0,width=7cm,clip]{1528fg5.eps}\end{figure}$ Figure 5: Relative differences in density, pression, temperature and square of the sound speed between models AC1 and OM1. For any variable x, the ratio $\frac{\Delta x}{x}$ is defined as $\frac{x_{\rm OM1}-x_{\rm AC1}}{x_{\rm AC1}}$ .
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In the text

$\begin{figure} \par\includegraphics[angle=0,width=7cm,clip]{1528fg6.eps}\end{figure}$ Figure 6: Same as Fig. 5, for models AC2 and OM2.
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In the text

$\begin{figure} \par\includegraphics[height=7cm,width=7cm,clip]{1528fg7.eps}\end{figure}$ Figure 7: Mass fractions of H, He, C, N, O, Ne, Mg and Z(which includes all the heavier elements), as a function of the fractional radius, in models AC1 (full lines) and OM1 (dashed lines).
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In the text

$\begin{figure} \par\includegraphics[height=7cm,width=7cm,clip]{1528fg8.eps}\end{figure}$ Figure 8: Same as Fig. 7 for models AC2 and OM2.
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In the text

$\begin{figure} \par\includegraphics[height=7cm,width=7cm,clip]{1528fg9.eps}\end{figure}$ Figure 9: Pulsation diagrams for AC1 ( a)), OM1 ( b)), AC2 ( c)), OM2 ( d)). The full lines represent the Brunt-Väisälä frequency, the dashed lines represent the Lamb frequency for l=1, 2, 3. Horizontal lines are drawn in each graphs for frequencies of 1 mHz and 2.5 mHz to help visualize the acoustic cavities.
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In the text

$\begin{figure} \par\includegraphics[angle=0,width=7cm,clip]{1528fg10.eps}\end{figure}$ Figure 10: Large separations devided by $\nu _0$ , inverse of twice the acoustic radius of the star, for models OM1 and AC1.
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In the text

$\begin{figure} \par\includegraphics[angle=0,width=7cm,clip]{1528fg11.eps}\end{figure}$ Figure 11: Large separations devided by $\nu _0$ , inverse of twice the acoustic radius of the star, for models OM2 and AC2.
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In the text

$\begin{figure} \par\includegraphics[angle=0,width=7cm,clip]{1528fg12.eps}\end{figure}$ Figure 12: Small separation for models AC1 and OM1, for l = 0 and l = 1, up to frequencies of 10 mHz. The vertical line corresponds to the cut-off frequencies. The oscillations due to the convective core are clearly seen for the overmetallic model. However they cannot be as clearly visible in real stars due to the cut-off frequencies.
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In the text

$\begin{figure} \par\includegraphics[angle=0,width=7cm,clip]{1528fg13.eps}\end{figure}$ Figure 13: Same as Fig. 12 for models AC2 and OM2.
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In the text

$\begin{figure} \par\includegraphics[angle=0,width=7cm,clip]{1528fg14.eps}\end{figure}$ Figure 14: Parameter $R_{n,l} = \frac{\pi}{2}\frac{D_{n,l}}{\Delta \nu_{n,l}}$ , for models AC1 and OM1, up to $\nu$ = 3 mHz, close to the cut-off frequencies; The beginning of the oscillations is evident in the overmetallic model for l = 0.
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In the text

$\begin{figure} \par\includegraphics[angle=0,width=7cm,clip]{1528fg15.eps}\end{figure}$ Figure 15: Same as Fig. 14, for models AC2 and OM2.
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In the text

$\begin{figure} \par\includegraphics[angle=0,width=7cm,clip]{1528fg16.eps}\end{figure}$ Figure 16: Second differences and Fourier transforms for models OM1 and AC1. The peaks below 2000 s are due to the helium ionisation zones while the peak around 6000 s is due to the bottom of the convective zone.
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In the text

$\begin{figure} \par\includegraphics[angle=0,width=7cm,clip]{1528fg17.eps}\end{figure}$ Figure 17: Same as Fig. 16 for models OM2 and AC2.
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In the text

$\begin{figure} \par\includegraphics[height=6cm,width=7cm,clip]{1528fg18.eps}\end{figure}$ Figure 18: Profiles of the thermodynamical parameter $\Gamma _1$ for models OM1 and AC1 ( top), OM2 and AC2 ( bottom). The kinks in $\Gamma _1$ are the reason for the two left peaks in Figs. 16 and 17, bottom graphs.
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In the text

$\begin{figure} \par\includegraphics[height=7cm,width=7cm,clip]{1528fg3.eps} \end{figure}$	Figure 3: Same as Fig. 2, except that here the overmetallic models have initial values: Z=0.04 and Y=0.33.
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$\begin{figure} \par\includegraphics[angle=0,width=7cm,clip]{1528fg5.eps}\end{figure}$	Figure 5: Relative differences in density, pression, temperature and square of the sound speed between models AC1 and OM1. For any variable x, the ratio $\frac{\Delta x}{x}$ is defined as $\frac{x_{\rm OM1}-x_{\rm AC1}}{x_{\rm AC1}}$ .
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$\begin{figure} \par\includegraphics[angle=0,width=7cm,clip]{1528fg6.eps}\end{figure}$	Figure 6: Same as Fig. 5, for models AC2 and OM2.
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$\begin{figure} \par\includegraphics[height=7cm,width=7cm,clip]{1528fg7.eps}\end{figure}$	Figure 7: Mass fractions of H, He, C, N, O, Ne, Mg and Z(which includes all the heavier elements), as a function of the fractional radius, in models AC1 (full lines) and OM1 (dashed lines).
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$\begin{figure} \par\includegraphics[height=7cm,width=7cm,clip]{1528fg8.eps}\end{figure}$	Figure 8: Same as Fig. 7 for models AC2 and OM2.
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$\begin{figure} \par\includegraphics[height=7cm,width=7cm,clip]{1528fg9.eps}\end{figure}$	Figure 9: Pulsation diagrams for AC1 ( a)), OM1 ( b)), AC2 ( c)), OM2 ( d)). The full lines represent the Brunt-Väisälä frequency, the dashed lines represent the Lamb frequency for l=1, 2, 3. Horizontal lines are drawn in each graphs for frequencies of 1 mHz and 2.5 mHz to help visualize the acoustic cavities.
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$\begin{figure} \par\includegraphics[angle=0,width=7cm,clip]{1528fg10.eps}\end{figure}$	Figure 10: Large separations devided by $\nu _0$ , inverse of twice the acoustic radius of the star, for models OM1 and AC1.
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$\begin{figure} \par\includegraphics[angle=0,width=7cm,clip]{1528fg11.eps}\end{figure}$	Figure 11: Large separations devided by $\nu _0$ , inverse of twice the acoustic radius of the star, for models OM2 and AC2.
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$\begin{figure} \par\includegraphics[angle=0,width=7cm,clip]{1528fg12.eps}\end{figure}$	Figure 12: Small separation for models AC1 and OM1, for l = 0 and l = 1, up to frequencies of 10 mHz. The vertical line corresponds to the cut-off frequencies. The oscillations due to the convective core are clearly seen for the overmetallic model. However they cannot be as clearly visible in real stars due to the cut-off frequencies.
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$\begin{figure} \par\includegraphics[angle=0,width=7cm,clip]{1528fg13.eps}\end{figure}$	Figure 13: Same as Fig. 12 for models AC2 and OM2.
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$\begin{figure} \par\includegraphics[angle=0,width=7cm,clip]{1528fg14.eps}\end{figure}$	Figure 14: Parameter $R_{n,l} = \frac{\pi}{2}\frac{D_{n,l}}{\Delta \nu_{n,l}}$ , for models AC1 and OM1, up to $\nu$ = 3 mHz, close to the cut-off frequencies; The beginning of the oscillations is evident in the overmetallic model for l = 0.
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$\begin{figure} \par\includegraphics[angle=0,width=7cm,clip]{1528fg15.eps}\end{figure}$	Figure 15: Same as Fig. 14, for models AC2 and OM2.
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$\begin{figure} \par\includegraphics[angle=0,width=7cm,clip]{1528fg16.eps}\end{figure}$	Figure 16: Second differences and Fourier transforms for models OM1 and AC1. The peaks below 2000 s are due to the helium ionisation zones while the peak around 6000 s is due to the bottom of the convective zone.
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$\begin{figure} \par\includegraphics[angle=0,width=7cm,clip]{1528fg17.eps}\end{figure}$	Figure 17: Same as Fig. 16 for models OM2 and AC2.
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$\begin{figure} \par\includegraphics[height=6cm,width=7cm,clip]{1528fg18.eps}\end{figure}$	Figure 18: Profiles of the thermodynamical parameter $\Gamma _1$ for models OM1 and AC1 ( top), OM2 and AC2 ( bottom). The kinks in $\Gamma _1$ are the reason for the two left peaks in Figs. 16 and 17, bottom graphs.
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