\begin{table}%t1 
\caption{Observed target stars: B- and A-type members of Per~OB2 
identified by Z99, supplemented with a number of early-type stars 
identified as members in pre-Hipparcos investigations (e.g., B52). The 
stars were observed in order of decreasing brightness, resulting in 
spectra for~29~distinct targets (62 exposures). Columns: 
(1) HD number (Hipparcos Catalogue field H71); 
(2) Hipparcos identifier (H1); 
(3) name; 
(4)~$V$~magnitude (H5); 
(5) spectral type and luminosity class;
(6) number of spectra obtained ($N$; subtractions refer to suspect
    exposures related to detector instability); 
(7) multiplicity (SB: spectroscopic binary; C: Hipparcos component
    binary -- $\rho$ and $\Delta Hp$ in Col.~11; G: Hipparcos
    acceleration binary; S: Hipparcos suspected non-single -- field H61); 
(8) Hipparcos membership (C: Z99 certain member; P: Z99 possible member;
    B: Z99 non-member, but B52 member); 
(9) Hipparcos parallax $\pi$ (H11; mas);
(10) Hipparcos parallax error $\sigma_\pi$ (H16; mas);
(11)~Hipparcos components. }
%%\centering
\par
\begin{tabular}{rcccllccccl}
\hline\hline 
\multicolumn{1}{c}{HD} & 
\multicolumn{1}{c}{HIP} & 
\multicolumn{1}{c}{Name} & 
\multicolumn{1}{c}{$V$} & 
\multicolumn{1}{c}{SpT+LCl} & 
\multicolumn{1}{c}{$N$} & 
\multicolumn{1}{c}{Mult.} & 
\multicolumn{1}{c}{Z99} & 
\multicolumn{1}{c}{$\pi$} & 
\multicolumn{1}{c}{$\sigma_\pi$} & 
\multicolumn{1}{l}{Hipparcos components}\\
\multicolumn{1}{c}{(1)} & 
\multicolumn{1}{c}{(2)} & 
\multicolumn{1}{c}{(3)} & 
\multicolumn{1}{c}{(4)} & 
\multicolumn{1}{c}{(5)} & 
\multicolumn{1}{c}{(6)} & 
\multicolumn{1}{c}{(7)} & 
\multicolumn{1}{c}{(8)} & 
\multicolumn{1}{c}{(9)} & 
\multicolumn{1}{c}{(10)} & 
\multicolumn{1}{l}{(11)} \\
\hline 
 18830 & 14207 &             & 8.34 & A0       & $3  $ & C    & C &  2.50& 1.42& $\rho=0{\farcs}335, \Delta Hp=2.27$~mag\\ 
 19216 & 14450 &             & 7.84 & B9V      & $3  $ &      & P &  4.81& 1.01& \\ 
 19567 & 14713 &             & 7.62 & B9       & $2-1$ &      & C &  4.54& 0.96& \\ 
 20113 & 15151 &             & 7.65 & B8       & $4-1$ &      & P &  3.43& 0.95& \\ 
 20987 & 15895 &             & 7.87 & B2V      & $2  $ & G    & C &  1.80& 1.08& \\ 
 21483 & 16203 &             & 7.06 & B3III    & $2-1$ &      & B &  1.60& 1.05& \\ 
 21856 & 16518 &             & 5.91 & B1V      & $1  $ &      & B &  1.99& 0.82& \\ 
 22114 & 16724 &             & 7.60 & B8Vp     & $2-1$ &      & P &  3.62& 0.99& \\ 
 22951 & 17313 & 40 Per      & 4.97 & B0.5V    & $1  $ & S    & C &  3.53& 0.88& \\ 
 23060 & 17387 &             & 7.51 & B2Vp     & $2  $ &      & P &  2.09& 0.93& \\ 
 23180 & 17448 & o~Per       & 3.84 & B1III    & $3-1$ & C+SB & P &  2.21& 0.84& $\rho=1{\farcs}019, \Delta Hp=2.91$~mag\\ 
 23268 & 17498 &             & 8.22 & A0       & $3  $ &      & C &  3.34& 0.99& \\ 
 23478 & 17631 &             & 6.68 & B3IV...  & $1  $ &      & B &  4.19& 1.03& \\ 
 23597 & 17698 &             & 8.19 & B8       & $3-1$ &      & C &  2.56& 1.01& \\ 
 23625 & 17735 &             & 6.57 & B2.5V    & $1  $ & C+SB & C &  2.63& 1.00& $\rho=3{\farcs}349, \Delta Hp=2.58$~mag\\ 
 23802 & 17845 &             & 7.45 & B5Vn     & $3  $ & C    & C &  3.09& 1.21& $\rho=2{\farcs}240, \Delta Hp=2.32$~mag\\ 
 24012 & 17998 &             & 7.84 & B5       & $2  $ &      & C &  1.82& 1.12& \\ 
 24131 & 18081 &             & 5.78 & B1V      & $2-2$ &      & C &  3.15& 0.84& \\ 
 24190 & 18111 &             & 7.43 & B2V      & $2-1$ & SB   & C &  2.04& 1.00& \\ 
 24398 & 18246 & $\zeta$~Per & 2.84 & B1Ib     & $1  $ &      & C &  3.32& 0.75& \\ 
 24583 & 18390 &             & 9.00 & B7V      & $5  $ &      & P &  3.31& 1.35& \\ 
 24640 & 18434 &             & 5.49 & B1.5V    & $1  $ & S    & P &  3.36& 0.76& \\ 
 24970 & 18621 &             & 7.44 & A0       & $3-1$ &      & P &  4.95& 0.99& \\ 
 25539 & 19039 &             & 6.87 & B3V      & $1  $ &      & C &  4.19& 0.97& \\ 
 25799 & 19178 &             & 7.05 & B3V...   & $2  $ & SB   & C &  2.78& 0.95& \\ 
 25833 & 19201 & AG~Per      & 6.70 & B5V:p    & $1-1$ & C+SB & C &  3.89& 1.31& $\rho=0{\farcs}803, \Delta Hp=1.81$~mag\\ 
 26499 & 19659 &             & 9.06 & B9       & $2  $ &      & C &  4.14& 1.30& \\ 
278942 & 17113 &             & 9.03 & B3III    & $2  $ & C    & C &  4.83& 1.21& $\rho=0{\farcs}149, \Delta Hp=0.78$~mag\\ 
281159 & 17465 &             & 8.51 & B5V      & $2  $ & C    & P &  4.52& 3.30& $\rho=0{\farcs}615, \Delta Hp=0.25$~mag\\ 
\hline
\end{tabular} 
\label{tab:1} 
\end{table}