All Figures

$\begin{figure} \par\includegraphics[width=8cm,clip]{Hl146_f1.ps} \end{figure}$ Figure 1: Positions of the known PG 1159 stars in the log $T_{\rm eff}$ - $\log g$ -diagram. The two known binary systems are shown as black dots, the new one is shown as square. Post-AGB evolutionary tracks are taken from Schönberner (1983, dashed lines, 0.546 $M_\odot$ and 0.565 $M_\odot$ ), Blöcker (1995, dashed line, 0.605 $M_\odot$ ), and Wood & Faulkner (1986, solid lines) (labels: mass in $M_\odot$ ). The dashed-dotted lines represent the theoretical red (Quirion et al. 2004) and blue edge (Gautschy priv.comm.) of the GW Vir instability strip.
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In the text

$\begin{figure} \par\includegraphics[height=8.3cm,width=15.35cm,clip]{Hl146_f2.ps} \end{figure}$ Figure 2: Spectrum of SDSS J212531.92-010745.9 (gray line, exposure time 3703 s), a PG 1159 NLTE model spectrum with $T_{\rm eff}$ = 90 000 K, $\log g$ = 7.60, and C/He = 0.05, N/He = 0.01 (thin black line), a blackbody spectrum with T = 8200 K (dashed line), representing the contribution from the irradiated companion, and the total model spectrum (thick black line). The Balmer series in emission ( top), belonging to the companion, and some helium and carbon lines ( bottom), belonging to the PG 1159 star, are marked.
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In the text

$\begin{figure} \par\includegraphics[height=7.3cm,width=15.4cm,clip]{Hl146_f3.ps} \end{figure}$ Figure 3: Light curve of all nights, overplotted the best sine fit with a period of 6.95616 h.
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In the text

$\begin{figure} \par\includegraphics[width=8.45cm,clip]{Hl146_f4.ps} \end{figure}$ Figure 4: Simulated light curve of a binary system, consisting of a PG 1159 star ( $T_{\rm eff}$ = 90 000 K) and an M dwarf ( $T_{\rm eff}$ = 3500 K, heated up to 8200 K), calculated with nightfall (black line) and the observed light curve of all nights, folded onto the orbital period. The shape of the light curve is well resampled, especially the broad dips.
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In the text

$\begin{figure} \par\includegraphics[height=7.3cm,width=15.4cm,clip]{Hl146_f3.ps} \end{figure}$	Figure 3: Light curve of all nights, overplotted the best sine fit with a period of 6.95616 h.
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$\begin{figure} \par\includegraphics[width=8.45cm,clip]{Hl146_f4.ps} \end{figure}$	Figure 4: Simulated light curve of a binary system, consisting of a PG 1159 star ( $T_{\rm eff}$ = 90 000 K) and an M dwarf ( $T_{\rm eff}$ = 3500 K, heated up to 8200 K), calculated with `nightfall` (black line) and the observed light curve of all nights, folded onto the orbital period. The shape of the light curve is well resampled, especially the broad dips.
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