Astronomy & Astrophysics

All Figures

$\begin{figure} \par\includegraphics[width=7.8cm,clip]{0823fg1a.eps}\vspace*{2.5m... ...eps}\vspace*{2.5mm} \includegraphics[width=7.8cm,clip]{0823fg1c.eps}\end{figure}$ Figure 1: Evolution of accreting white dwarf models of sequence N3, R3 & TB3, for which $\ensuremath {{M}_{\rm WD, init}}$ = 0.8 $\ensuremath {{M}_\odot }$ and $\dot{M}=2\times10^{-8}~{M_{\odot}/\rm yr}$ , in the $\log \rho - \log T$ plane. The boundary between the CO core and the helium envelope, defined though Y=0.1, is indicated by a filled circle for each model.
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In the text

$\begin{figure} \par\hspace*{-1.2mm}\includegraphics[width=8.7cm,clip]{0823fg2a.eps}\vspace*{2.5mm} \includegraphics[width=8.7cm,clip]{0823fg2b.eps}\end{figure}$ Figure 2: Upper panel: angular velocity in units of the local Keplerian value as a function of the mass coordinate in model sequence R3 when $M_{\rm {WD}}$ = 0.805, 0.812 and 0.821 $\ensuremath {{M}_\odot }$ . The filled circles indicate the boundary of the CO core and helium envelope, as defined in Fig. 1, where the helium mass fraction is 0.1. Lower panel: rotational energy dissipation due to friction (Eq. (1)) at the same evolutionary epochs as in the upper panel. The thin solid line denotes the energy generation rate due to nuclear reactions when $M_{\rm {WD}}$ = 0.821 $\ensuremath {{M}_\odot }$ .
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In the text

$\begin{figure} \par\includegraphics[width=8.4cm,clip]{0823fig3.eps}\end{figure}$ Figure 3: Mass transfer rate as a function of the helium star mass, for a binary system consisting initially of an 0.6 $\ensuremath {{M}_\odot }$ helium star and an 0.8 $\ensuremath {{M}_\odot }$ CO white dwarf (the latter here being approximated by a point mass). Mass transfer is initiated by gravitational wave radiation. The solid line illustrates the case where mass loss due to helium flashes is considered, while the dashed line was computed assuming that no mass loss occurs.
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In the text

$\begin{figure} \par\includegraphics[width=8.6cm,clip]{0823fig4.eps}\end{figure}$ Figure 4: Evolution in the HR diagram of the helium star (initial mass 0.6 $\ensuremath {{M}_\odot }$ ) component of the binary system considered in Fig. 3, for the case with nova-induced mass loss.
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In the text

$\begin{figure} \par\includegraphics[width=8.2cm,clip]{0823fg5a.eps}\vspace*{3mm} \includegraphics[width=8.2cm,clip]{0823fg5b.eps}\end{figure}$ Figure 5: a) Chemical profiles in the outer layers of the white dwarf models of sequence R3 when $M_{\rm {WD}}$ = 0.8 $\ensuremath {{M}_\odot }$ (initial model, thin lines), and $M_{\rm {WD}}$ = 0.822 $\ensuremath {{M}_\odot }$ (thick lines) which is immediate before the helium ignition. The solid and dotted-dashed lines give the mass fraction of $\ensuremath {{^{4}{\rm He}}}$ and $\ensuremath {{^{12}{\rm C}}}$ respectively, as a function of the mass coordinate. The dashed line denotes the mass fraction of $\ensuremath {{^{22}{\rm Ne}}}$ . b) Same as in a) but after the ignition of helium. The dotted line denotes the neutron density, for which the scale is given at the right side.
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In the text

$\begin{figure} \par\includegraphics[width=7.8cm,clip]{0823fg1a.eps}\vspace{2.5m... ...eps}\vspace{2.5mm} \includegraphics[width=7.8cm,clip]{0823fg1c.eps}\end{figure}$	Figure 1: Evolution of accreting white dwarf models of sequence N3, R3 & TB3, for which $\ensuremath {{M}_{\rm WD, init}}$ = 0.8 $\ensuremath {{M}_\odot }$ and $\dot{M}=2\times10^{-8}~{M_{\odot}/\rm yr}$ , in the $\log \rho - \log T$ plane. The boundary between the CO core and the helium envelope, defined though Y=0.1, is indicated by a filled circle for each model.
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$\begin{figure} \par\includegraphics[width=8.6cm,clip]{0823fig4.eps}\end{figure}$	Figure 4: Evolution in the HR diagram of the helium star (initial mass 0.6 $\ensuremath {{M}_\odot }$ ) component of the binary system considered in Fig. 3, for the case with nova-induced mass loss.
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