Table 1: X-ray detected Praesepe members. $\Delta r$ is the distance to the optical position. The column labeled "set'' indicates whether the source was detected on the summed dataset (S) or only on the MOS (M) or PN (P) single datasets. Count rates are MOS equivalent count rates, except where set = P, when they are PN count rates. Luminosities were derived using the appropriate conversion factors (see text).

Name		 RA$_{\rm X}$ DEC$_{\rm X}$ $\Delta r$ ML set count rate $L_{\rm X}$ V B-V Mem Notes
  (J2000) ( $\>\hbox{$^{\prime\prime}$ }\>$)     (cts/ksec) (a)   $(R-I)_{\rm c}$*   (b)

KW 154		 $8\>39\>09.24$ $19\>35\>32.5$ 2.02 39.5 S $ 0.71 \pm 0.14$ 1.87 8.50 0.25 Y  
KW 155 $8\>39\>10.20$ $19\>40\>45.1$ 2.73 24.8 S $ 0.70 \pm 0.17$ 1.87 9.42 0.41 Y  
KW 181 $8\>39\>25.05$ $19\>27\>35.2$ 1.64 8056.9 S $17.45 \pm 0.43$ 46.28 10.47 0.59 Y SB, X
KW 184 $8\>39\>28.66$ $19\>28\>26.5$ 1.56 280.2 S $ 1.68 \pm 0.16$ 4.45 11.56 0.90 Y SB2, X
KW 198 $8\>39\>38.42$ $19\>26\>28.5$ 1.57 229.5 S $ 1.33 \pm 0.13$ 3.53 12.59 0.96 Y  
KW 208 $8\>39\>46.00$ $19\>22\>01.5$ 3.22 1139.7 S $ 8.06 \pm 0.44$ 21.38 10.66 0.58 Y  
KW 212 $8\>39\>50.76$ $19\>32\>27.2$ 0.68 15189.1 S $17.37 \pm 0.33$ 46.08 6.59 0.96 Y K0III, X
KW 213 $8\>39\>50.91$ $19\>33\>02.9$ 1.10 212.0 S $ 1.20 \pm 0.12$ 3.18 11.81 0.80 Y X
KW 217 $8\>39\>52.45$ $19\>18\>45.7$ 1.83 1399.0 S $ 9.13 \pm 0.49$ 24.22 10.23 0.51 Y X
KW 224 $8\>39\>56.54$ $19\>33\>11.3$ 0.98 53890.7 S $45.14 \pm 0.50$ 119.73 7.32 0.19 Y SB1, X
KW 236 $8\>39\>59.99$ $19\>33\>59.9$ 1.50 145.5 S $ 0.74 \pm 0.09$ 1.96 11.94 1.00 Y SB, X
KW 237 $8\>40\>00.05$ $19\>34\>41.8$ 1.48 99.2 S $ 0.63 \pm 0.09$ 1.67 12.86 1.00 Y X
KW 246 $8\>40\>03.95$ $19\>47\>06.2$ 4.42 17.9 M $ 3.49 \pm 1.05$ 9.25 12.01 0.84 Y? SB1
KW 250 $8\>40\>04.94$ $19\>43\>46.2$ 0.78 173.0 S $ 1.57 \pm 0.17$ 4.16 9.79 0.47 Y  
KW 257 $8\>40\>06.30$ $19\>18\>27.1$ 1.70 211.9 S $ 3.27 \pm 0.35$ 8.67 11.00 0.77 Y SB, PhB
KW 263 $8\>40\>09.68$ $19\>37\>18.3$ 1.51 348.1 S $ 1.61 \pm 0.13$ 4.28 12.02 0.81 Y X
KW 268 $8\>40\>12.35$ $19\>38\>22.3$ 0.90 1191.2 S $ 3.70 \pm 0.19$ 9.83 9.89 0.48 Y SB1
KW 279 $8\>40\>20.72$ $19\>41\>12.3$ 0.37 525.7 S $ 3.52 \pm 0.26$ 9.35 7.70 0.20 Y SB1
KW 283 $8\>40\>22.13$ $19\>40\>11.5$ 0.66 1335.6 S $ 5.18 \pm 0.24$ 13.74 6.44 1.02 Y K0.5IIIa
KW 287 $8\>40\>23.28$ $19\>40\>22.8$ 1.18 2369.4 S $ 7.98 \pm 0.31$ 21.16 10.37 0.59 Y SB1
KW 288 $8\>40\>22.75$ $19\>27\>54.0$ 0.52 1863.4 S $ 7.67 \pm 0.33$ 20.35 10.71 0.58 Y X
KW 293 $8\>40\>25.60$ $19\>28\>33.7$ 1.71 1609.4 S $ 4.70 \pm 0.21$ 12.47 9.89 0.48 Y X
KW 295 $8\>40\>26.12$ $19\>41\>11.6$ 0.42 227.1 S $ 1.84 \pm 0.18$ 4.87 9.41 0.41 Y  
KW 299 $8\>40\>27.50$ $19\>39\>21.9$ 2.39 45.1 S $ 0.54 \pm 0.10$ 1.44 13.17 1.07 Y  
KW 313 $8\>40\>33.37$ $19\>38\>02.7$ 2.75 196.5 S $ 1.71 \pm 0.19$ 4.54 12.20 0.89 Y  
KW 322 $8\>40\>39.92$ $19\>40\>10.8$ 4.01 685.4 S $ 4.15 \pm 0.28$ 11.01 10.87 0.68 Y SB1, X
KW 326 $8\>40\>42.40$ $19\>33\>59.7$ 2.86 133.1 S $ 1.21 \pm 0.15$ 3.20 11.34 0.72 Y  
KW 334 $8\>40\>47.97$ $19\>39\>32.3$ 1.32 125.5 S $ 3.39 \pm 0.47$ 8.99 11.02 0.72 Y PhB, X
KW 341 $8\>40\>52.40$ $19\>28\>58.0$ 2.76 234.8 S $ 4.78 \pm 0.52$ 12.66 10.30 0.52 Y SB1
JC 143 $8\>39\>03.01$ $19\>31\>58.5$ 1.57 377.2 S $ 3.73 \pm 0.31$ 9.90 16.92 1.57 Y PhB, X
JS 267 $8\>39\>04.09$ $19\>31\>24.5$ 3.02 26.9 S $ 0.68 \pm 0.16$ 1.81 13.75 1.21 Y  
JS 298 $8\>39\>31.84$ $19\>24\>18.3$ 1.17 229.8 S $ 1.68 \pm 0.17$ 4.47 17.71 1.59* Y?  
JS 305 $8\>39\>38.56$ $19\>44\>19.5$ 2.31 69.1 S $ 1.25 \pm 0.19$ 3.31 17.92   Y? (c)
JS 329 $8\>40\>00.78$ $19\>18\>35.5$ 0.86 173.9 S $ 2.03 \pm 0.23$ 5.38 14.43 1.38 Y  
JS 349 $8\>40\>15.35$ $19\>27\>31.7$ 3.11 49.7 S $ 0.59 \pm 0.11$ 1.56 13.91 1.33 Y  
JS 706 $8\>39\>15.15$ $19\>43\>31.6$ 0.42 420.6 S $ 5.41 \pm 0.45$ 14.36 16.96 1.48* Y  
JS 718 $8\>40\>04.26$ $19\>24\>51.0$ 1.16 330.5 S $ 1.80 \pm 0.16$ 4.78 18.02 1.73* Y  
HSHJ 246 $8\>39\>03.31$ $19\>24\>06.3$ 9.95 63.5 S $ 2.07 \pm 0.35$ 5.49   1.70* Y  
HSHJ 258 $8\>39\>18.78$ $19\>22\>46.0$ 5.63 10.4 P $ 2.31 \pm 0.76$ 1.33   2.01* Y PhB
HSHJ 283 $8\>39\>41.65$ $19\>29\>01.3$ 1.17 30.0 S $ 0.34 \pm 0.08$ 0.89   2.07* Y PhB
HSHJ 289 $8\>39\>47.25$ $19\>39\>34.9$ 1.09 132.5 S $ 0.88 \pm 0.11$ 2.32   1.68* Y  
HSHJ 291 $8\>39\>54.52$ $19\>27\>37.9$ 1.51 91.4 S $ 0.57 \pm 0.08$ 1.51   1.77* Y  
HSHJ 293 $8\>40\>02.70$ $19\>40\>35.6$ 2.90 48.3 S $ 0.58 \pm 0.11$ 1.53   1.45* Y  
HSHJ 302 $8\>40\>11.62$ $19\>39\>12.7$ 0.79 796.8 S $ 2.91 \pm 0.18$ 7.73   1.45* Y  
HSHJ 328 $8\>40\>41.77$ $19\>30\>05.3$ 4.79 32.5 S $ 0.61 \pm 0.13$ 1.62   2.07* Y PhB
WRS 4 $8\>39\>12.62$ $19\>30\>14.4$ 2.82 100.7 S $ 0.38 \>(g) $ 0.88 20.79   Y (d)
J0839531+192403 $8\>39\>53.23$ $19\>24\>04.0$ 0.41 766.5 S $ 3.31 \pm 0.20$ 8.77     Y? (e)
J0840394+194255 $8\>40\>39.32$ $19\>42\>54.1$ 2.18 35.3 M $ 2.06 \pm 0.49$ 5.47     Y (f)
(a) Luminosity in the ROSAT band (0.1-2.4 keV) in units of 1028 erg s-1; (b) An X indicates ROSAT detections.
(c) $V-I_{\rm k} = 2.41$; (d) $V-I_{\rm k} = 3.46$; (e) J=13.94, $K_{\rm s} = 13.03$; (f) J=13.48, $K_{\rm s} = 12.61$.
(g) The X-ray source is blended with GSC2 N231230081115: the total count rate is $1.14\pm 0.13$, WRS 4 contributes by $\sim$1/3 (see text)
Star names are from Klein-Wassink (1927, KW), Jones & Cudworth (1983, JC), Jones & Stauffer (1991, JS), Hambly et al. (1995, HSHJ),
and Williams et al. (1995, WRS). For the last two stars from Adams et al. (2002) the 2MASS identification is given.


Source LaTeX | All tables | In the text