\begin{table}%ta2 %\centering \par \caption{\label{tab:old}Properties of the previously known PCEBs.} \begin{tabular}{llccccccl} \hline \hline \noalign{\smallskip} Object & Alt. Name & \multicolumn{1}{c}{$P$} & \multicolumn{1}{c}{$M_{\rm WD}$} & \multicolumn{1}{c}{$M_{\rm 2}$} & \multicolumn{1}{c}{$T_{\rm WD}$} & \multicolumn{1}{c}{$t_{\rm cool}$} & \multicolumn{1}{c}{$P_{\rm CE}$} & Ref. \\ & & \multicolumn{1}{c}{(d)} & \multicolumn{1}{c}{(\Msun)} & \multicolumn{1}{c}{(\Msun)} & \multicolumn{1}{c}{(K)} & \multicolumn{1}{c}{(Gyr)} & \multicolumn{1}{c}{(d)} & \\ \hline WD0137-3457 & & 0.080& 0.390 $\pm$ 0.035 & 0.053 $\pm$ 0.006 & 16500 & 0.179 & 0.082 & 1 \\ GD~448 & HR~Cam & 0.103& 0.410 $\pm$ 0.010 & 0.096 $\pm$ 0.040 & 19000 & 0.118 & 0.104 & 2, 3 \\ NN~Ser & PG~$1550+131$ & 0.130& 0.535 $\pm$ 0.012 & 0.111 $\pm$ 0.004 & 57000 & 0.001 & 0.130 & 4 \\ LTT~560 & & 0.148& 0.520 $\pm$ 0.120 & 0.190 $\pm$ 0.050 & 7500 & 1.040 & 0.162 & 5 \\ MS~Peg & GD~$245$ & 0.174& 0.480 $\pm$ 0.020 & 0.220 $\pm$ 0.020 & 22170 & 0.027 & 0.174 & 6 \\ LM~Com & PG~$1224+309$ & 0.259& 0.450 $\pm$ 0.050 & 0.280 $\pm$ 0.050 & 29300 & 0.032 & 0.259 & 7 \\ CC~Cet & PG~$0308+096$ & 0.284& 0.390 $\pm$ 0.100 & 0.180 $\pm$ 0.050 & 26200 & 0.000 & 0.284 & 8 \\ CSS~080502 & & 0.149& 0.350 $\pm$ 0.040 & 0.320 $\pm$ 0.000 & 17505 & 0.130 & 0.288 & 9, 10 \\ RR~Cae & LFT~$349$ & 0.303& 0.440 $\pm$ 0.022 & 0.182 $\pm$ 0.013 & 7540 & 2.037 & 0.313 & 11 \\ BPM~6502 & LTT~$3943$ & 0.337& 0.500 $\pm$ 0.050 & 0.170 $\pm$ 0.010 & 21000 & 0.036 & 0.337 & 12, 13, 14 \\ GK~Vir & PG~$1413+015$ & 0.344& 0.510 $\pm$ 0.040 & 0.100 $\pm$ 0.000 & 48800 & 0.002 & 0.344 & 15, 16 \\ EC~$14329-1625$ & & 0.350& 0.620 $\pm$ 0.110 & 0.380 $\pm$ 0.070 & 14575 & 0.220 & 0.421 & 17 \\ EC~$12477-1738$ & & 0.362& 0.610 $\pm$ 0.080 & 0.380 $\pm$ 0.070 & 17718 & 0.113 & 0.402 & 17 \\ DE~CVn & J~$1326+4532$ & 0.364& 0.530 $\pm$ 0.040 & 0.410 $\pm$ 0.060 & 8000 & 0.895 & 0.518 & 18 \\ EC~$13349-3237$ & & 0.470& 0.460 $\pm$ 0.110 & 0.500 $\pm$ 0.050 & 35010 & 0.000 & 0.470 & 17 \\ RXJ$2130.6+4710$ & & 0.521& 0.554 $\pm$ 0.017 & 0.555 $\pm$ 0.023 & 18000 & 0.088 & 0.530 & 19 \\ HZ~9 & & 0.564& 0.510 $\pm$ 0.100 & 0.280 $\pm$ 0.040 & 17400 & 0.086 & 0.564 & 20, 21, 22, 23 \\ UX~CVn & HZ~$22$ & 0.570& 0.390 $\pm$ 0.050 & 0.420 $\pm$ 0.000 & 28000 & 0.000 & 0.570 & 24 \\ UZ~Sex & PG~$1026+0014$ & 0.597& 0.650 $\pm$ 0.230 & 0.220 $\pm$ 0.050 & 19900 & 0.084 & 0.597 & 8, 25 \\ EG~UMa & Case~1 & 0.668& 0.640 $\pm$ 0.030 & 0.420 $\pm$ 0.040 & 13100 & 0.313 & 0.688 & 26 \\ RE~J$2013+4002$ & & 0.706& 0.560 $\pm$ 0.030 & 0.180 $\pm$ 0.040 & 49000 & 0.002 & 0.706 & 27, 28 \\ RE~J$1016-0520$ & & 0.789& 0.600 $\pm$ 0.020 & 0.150 $\pm$ 0.020 & 55000 & 0.002 & 0.789 & 27, 28 \\ IN~CMa & J$0720-3146$ & 1.260& 0.570 $\pm$ 0.030 & 0.430 $\pm$ 0.030 & 52400 & 0.002 & 1.260 & 27, 29 \\ Feige~24 & FS~Cet & 4.232& 0.570 $\pm$ 0.030 & 0.390 $\pm$ 0.020 & 57000 & 0.001 & 4.232 & 30 \\ IK~Peg & BD~$+18$~$4794$& 21.722& 1.190 $\pm$ 0.050 & 1.700 $\pm$ 0.100 & 35500 & 0.027 & 21.722 & 29, 31\\ \hline \end{tabular} \tablebib{(1) \citet{burleighetal06-1}; (2)~\citet{marsh+duck96-1}, (3) \citet{maxtedetal98-1}; (4)~\citet{parsonsetal10-1}; (5)~\citet{tappertetal07-1}; %MS Peg (6)~\citet{schmidtetal95-3}; %LM Com (7)~\citet{oroszetal99-1}; %CC Cet (8)~\citet{safferetal93-1}; %CSS 080502 (9)~\citet{drakeetal09-1}; (10)~\citet{pyrzasetal09-1}; %RR Cae (11)~\citet{maxtedetal07-2}; %BPM 6502 (12)~\citet{kawkaetal00-1}; (13)~\citet{bragagliaetal95-1}; (14)~\citet{koesteretal79-1}; %GK Vir (15)~\citet{fulbrightetal93-1}; (16)~\citet{greenetal78-1}; %EC 14329-1625 (17)~\citet{tappertetal09-1}; %EC 12477-1738 %(17) \citet{tappertetal09-1}, %DE CVn (18)~\citet{vandenbesselaaretal07-1}; %EC13349-3237 %(19) \citet{tappertetal09-1}, %RXJ2130.6+4710 (19)~\citet{maxtedetal04-1}; %HZ 9 (20)~\citet{stauffer87-1}; (21)~\citet{lanning+pesch81-1}; (22) \citet{guinan+sion84-1}; (23) \citet{schreiber+gaensicke03-1}; %UX CVn (24)~\citet{Hillwigetal00-1}; %UZ Sex %(8) \citet{safferetal93-1}, (25) \citet{kepler+nelan93-1} %EG UMa (26)~\citet{bleachetal00-1}; %RE J2013+4002 (27)~\citet{vennesetal99-2}; (28)~\citet{bergeronetal94-1}; %RE J1016-0520 %(27) \citet{vennesetal99-2}, %(28) \citet{bergeronetal94-1}, %IN CMa %(27) \citet{vennesetal99-2}, (29) \citet{davisetal10-1}, %Feige 24 (30)\citet{kawkaetal08-1}, %IK Peg %(29) \citet{davisetal10-1}, (31)~\citet{landsmanetal93-1}.} \end{table}