\begin{table}%t6
\caption {\label{a_p}Frequencies, amplitudes, and phases of the leastsquares sine fits to the observed first moment. }
%\centerline
 {\begin{tabular}{cccc}
\hline
\hline 
ID & Frequency & Amplitude & Phase \\
   & (d$^{-1}$) & (km~s$^{-1}$) & (rad)\\              
\hline 
$f_1$   & 5.4869(1) & 38.8(2) & 3.139(6) \\
$2 f_1$ & 10.9738(1) & 3.0(2) & 5.45(8) \\
$3 f_1$ & 16.4607(1) & 4.7(2) & 3.30(5) \\
$4 f_1$ & 21.9476(1) & 3.6(2) & 5.30(7) \\
$5 f_1$ & 27.4345(2) & 1.7(2) & 0.8(1)  \\
$f_2^s$ & 8.4079(2) & 1.5(2) & 4.2(1) \\
$f_3^s$ & 0.3046(2) & 1.1(2) & 2.0(2) \\
$f_4^s$ & 7.1037(3) & 1.0(2) & 2.7(2) \\
$f_1+f_2^s$ & 13.8948(3) & 0.8(2) & 6.3(3) \\ 
\hline
\end{tabular}}
\par
\smallskip
 {The error estimates in units of the last digit are given in brackets. The adopted reference epoch for $\phi=0.0$ corresponds to HJD~2~447~963.2564.}
\end{table}