Table A.1: X-ray sources detected in CMa R1 by ROSAT. CMaX Err Cnt/ks S/N log$L_{\rm x}$ RA Dec R AV J H K Age Mass ('') J2000 J2000 (mag) (mag) (mag) (mag) (mag) (Myr) ($M_{\odot }$) 1 30 16.7 $\pm$ 1.6 10.4 31.25 6 57 52.6 -11 27 23 9.7 1.0 8.9 8.7 8.6 <1 3.0-5.0 2 30 5.0 $\pm$ 0.8 6.3 30.72 6 58 17.6 -11 37 10 15.7 1.0 14.5 13.9 13.8 05-10 1.0-1.5 3a 30 17.9 $\pm$ 1.6 11.2 31.28 6 58 42.6 -11 42 00 9.0 0.5 8.4 8.2 8.1 <1 3.0-5.0 (a) HD 51896 (F5) 4b 30 19.4 $\pm$ 1.4 13.9 31.31 6 59 02.0 -11 00 38 10.8 0.4 11.5 11.4 11.4 05-10 1.5-2.0 (b) SS 75 5c 30 5.0 $\pm$ 0.9 5.6 30.72 6 59 10.7 -11 40 03 8.3 0.5 7.7 7.5 7.4 <1? >5 (c) HD 52014 (F5) 6 30 7.0 $\pm$ 0.9 7.8 30.87 6 59 10.7 -11 57 30 13.0 1.0 11.2 10.8 10.7 02-05 2.0-3.0 7 30 5.1 $\pm$ 0.8 6.4 30.73 6 59 31.0 -11 58 18 11.8 0.9 11.0 10.6 10.6 02-05 2.0-3.0 8 20 2.4 $\pm$ 0.6 4.0 30.40 6 59 51.1 -11 15 52 12.7 0.5 11.2 10.7 10.5 01-02 2.0-3.0 9 12 1.4 $\pm$ 0.4 3.5 30.17 (7 00 00.5) (-11 14 09) - - - - - - - 10 30 5.1 $\pm$ 0.7 7.3 30.73 7 00 03.4 -11 47 45 - - 9.6 9.6 9.6 < 1 3.0-5.0 11 10 2.8 $\pm$ 0.5 5.6 30.47 7 00 03.8 -11 15 26 14.8 0.4 13.7 13.2 13.0 20-50 1.0-1.5 12 5 3.7 $\pm$ 0.6 6.2 30.59 7 00 05.2 -11 31 46 14.8 0.8 13.4 12.8 12.7 05-10 1.0-1.5 13 12 1.2 $\pm$ 0.3 4.0 30.10 7 00 08.0 -11 37 00 14.9 0.5 14.1 13.4 13.2 05-10 1.0-1.5 14 12 2.2 $\pm$ 0.4 5.5 30.36 7 00 12.5 -11 34 33 16.6 0.8 13.8 13.1 12.9 02-05 1.0-1.5 15 10 1.9 $\pm$ 0.4 4.8 30.30 (7 00 14.5) (-11 18 51) - - - - - - - 16 10 2.0 $\pm$ 0.5 4.0 30.32 7 00 17.0 -11 08 03 13.7 0.4 12.6 12.4 12.3 >50 1.5-2.0 17 9 1.3 $\pm$ 0.3 4.3 30.14 (7 00 19.8) (-11 23 20) - - - - - - - 18 8 1.1 $\pm$ 0.3 3.7 30.06 7 00 26.5 -11 26 33 14.9 0.8 13.1 12.4 12.2 02-05 1.0-1.5 19 30 4.6 $\pm$ 0.8 5.8 30.69 7 00 27.1 -11 51 26 13.4 0.8 12.4 12.1 12.0 10-20 1.5-2.0 20d 5 62.7 $\pm$ 1.9 33.0 31.82 7 00 37.6 -11 14 45 7.8 0.7 6.6 6.0 5.9 <1? >5 (d) HD 52385 (K0) 21 30 41.6 $\pm$ 1.9 21.9 31.64 7 00 40.4 -11 04 35 12.3 0.9 10.6 9.9 9.7 <1 1.0-1.5 22 6 2.0 $\pm$ 0.4 5.0 30.32 (7 00 41.3) (-11 34 50) - - - - - - - 23 5 3.4 $\pm$ 0.5 6.8 30.55 7 00 43.4 -11 17 14 14.3 0.5 12.9 12.3 12.2 02-05 1.5-2.0 24* 8 1.1 $\pm$ 0.4 2.8 30.06 7 00 45.4 -11 31 00 16.9 0.5 15.9 15.6 15.0 ?? ?? (IRx) 25 8 0.4 $\pm$ 0.2 2.0 29.62 7 00 45.5 -11 20 29 17.0 0.8 16.0 15.7 15.6 ?? ?? 26 12 1.2 $\pm$ 0.3 4.0 30.10 7 00 54.6 -11 34 12 14.0 0.8 13.2 12.8 12.7 20-50 1.0-1.5 27* 10 2.2 $\pm$ 0.5 4.4 30.36 7 00 55.5 -11 21 45 15.7 0.7 14.6 14.3 14.1 01-02 0.1-0.5 (IRx) 28 8 0.9 $\pm$ 0.3 3.0 29.98 7 00 55.8 -11 26 25 15.8 0.8 13.6 12.8 12.6 ?? ?? 29 5 2.5 $\pm$ 0.4 6.3 30.42 7 01 00.8 -11 19 29 15.4 1.0 12.8 12.1 11.9 <1 0.5-1.0 30 12 2.1 $\pm$ 0.5 4.2 30.34 7 01 04.1 -11 39 48 16.4 0.7 15.2 14.4 14.2 05-10 0.1-0.5 31 9 0.8 $\pm$ 0.3 2.7 29.93 7 01 06.9 -11 31 23 10.6 0.7 9.4 9.0 8.8 <1 3.0-5.0 32 8 2.1 $\pm$ 0.4 5.3 30.34 7 01 11.2 -11 27 50 11.4 0.9 10.8 10.6 10.5 02-05 2.0-3.0 33 15 0.9 $\pm$ 0.3 3.0 29.98 7 01 13.1 -11 21 01 16.4 1.0 14.9 14.4 14.3 ?? ?? 34 8 1.3 $\pm$ 0.3 4.3 30.14 7 01 16.3 -11 25 58 15.2 1.0 13.7 13.0 12.9 05-10 1.0-1.5 35 8 0.7 $\pm$ 0.3 2.3 29.87 7 01 20.1 -11 17 44 15.6 0.7 13.3 12.9 12.8 20-50 1.0-1.5 36 15 1.1 $\pm$ 0.3 3.7 30.06 7 01 24.4 -11 09 06 16.2 0.5 14.8 14.2 14.1 20-50 0.5-1.0 37 15 2.1 $\pm$ 0.4 5.3 30.34 (7 01 25.0) (-11 08 50) - - - - - - - 38 5 3.5 $\pm$ 0.4 8.8 30.57 7 01 26.8 -11 28 21 13.5 0.8 12.3 12.0 11.9 10-20 1.5-2.0 39 8 0.8 $\pm$ 0.3 2.7 29.93 7 01 29.2 -11 21 30 15.4 0.8 14.1 13.5 13.5 10-20 1.0-1.5 40 10 2.0 $\pm$ 0.4 5.0 30.32 7 01 30.4 -11 22 29 16.9 1.2 15.4 14.8 14.8 ?? ?? 41 8 1.6 $\pm$ 0.4 4.0 30.23 7 01 34.0 -11 25 33 15.3 0.8 13.8 13.2 13.1 10-20 1.0-1.5 42 10 1.8 $\pm$ 0.4 4.5 30.28 (7 01 34.3) (-11 11 16) - - - - - - - 43 15 0.6 $\pm$ 0.3 2.0 29.80 07 01 35.1 -11 36 38 14.3 1.3 12.1 11.8 11.7 10-20 1.5-2.0 44 8 1.2 $\pm$ 0.3 4.0 30.10 7 01 35.8 -11 17 36 13.6 0.8 12.8 12.5 12.4 10-20 1.0-1.5 45 10 1.2 $\pm$ 0.4 3.0 30.10 7 01 41.1 -11 32 57 12.9 1.0 12.2 11.9 11.9 10-20 1.5-2.0 46 15 1.4 $\pm$ 0.4 3.5 30.17 (7 01 43.0) (-11 10 20) - - - - - - - 47 8 2.1 $\pm$ 0.4 5.3 30.34 7 01 45.9 -11 30 33 15.4 0.7 13.4 12.7 12.5 01-02 0.5-1.0 48e 15 2.7 $\pm$ 0.4 6.8 30.45 7 01 49.3 -11 18 07 7.5 1.7 6.3 6.2 6.0 ?? ?? (e) GU CMa, HD 52721 (B2V), C 63 , SEI 158 49 9 1.5 $\pm$ 0.4 3.8 30.20 7 01 49.5 -11 16 41 12.2 1.7 10.8 10.3 10.2 02-05 2.0-3.0 50 12 1.1 $\pm$ 0.3 3.7 30.06 7 01 52.4 -11 20 18 13.4 1.3 12.1 11.7 11.5 05-10 1.5-2.0 51 8 1.3 $\pm$ 0.4 3.3 30.14 7 01 56.3 -11 24 07 16.5 1.2 14.3 13.6 13.4 10-20 1.0-1.5 52 8 2.3 $\pm$ 0.4 5.8 30.38 7 01 58.7 -11 15 45 13.5 1.7 12.3 11.6 11.5 01-02 2.0-3.0 53 14 1.5 $\pm$ 0.4 3.8 30.20 7 02 04.4 -11 19 44 14.1 1.2 13.4 13.0 12.9 >50 05-1.0 54 15 0.5 $\pm$ 0.3 1.7 29.72 (7 02 05.5) (-11 26 50) - - - - - - - 55 30 0.6 $\pm$ 0.3 2.0 29.80 (7 02 07.4) (-11 17 11) - - - - - - - 56 30 5.3 $\pm$ 0.8 6.6 30.75 7 02 38.9 -11 30 39 12.8 0.9 9.9 8.9 8.6 ?? ?? 57f 30 2.3 $\pm$ 1.0 2.3 30.40 7 02 42.6 -11 27 12 8.0 1.6 7.8 7.8 7.7 <1? >5 (f) FZ CMa (B2.5), C 67, SEI 159 58 30 2.0 $\pm$ 1.0 2.0 30.32 7 02 47.3 -11 28 08 16.6 1.6 14.9 14.3 14.1 >50 1.0-1.5 59 30 1.9 $\pm$ 1.0 2.0 30.31 7 02 51.3 -11 24 03 17.5 4.0 14.6 13.7 13.4 05-10 1.0-1.5 60 30 1.5 $\pm$ 0.9 1.6 30.20 7 03 30.4 -11 48 07 13.7 2.4 13.5 13.0 12.8 20-50 1.0-1.5 61x 30 1.7 $\pm$ 0.9 1.9 30.27 7 03 33.5 -11 34 27 15.2 2.6 13.5 12.8 12.5 05-10 1.0-1.5 62x 30 1.5 $\pm$ 0.9 1.7 30.20 7 03 42.1 -11 35 14 15.5 2.5 13.4 12.6 12.4 02-05 1.5-2.0 63*,g,x 30 2.5 $\pm$ 1.0 2.5 30.43 7 03 43.2 -11 33 06 9.1 3.4 6.5 5.2 3.8 ?? ?? (g) Z CMa (Bpe), C 76, SEI 161 (IRx), (X) 64x 30 2.9 $\pm$ 1.1 2.7 30.49 7 03 47.5 -11 31 49 13.8 1.3 13.5 12.8 12.6 01-02 0.5-1.0 (X) 65 30 1.2 $\pm$ 0.8 1.5 30.11 7 03 48.2 -11 41 46 14.0 0.3 13.6 12.8 12.6 ?? ?? 66j,x 30 6.2 $\pm$ 1.4 4.3 30.82 7 03 51.5 -11 34 56 - - 11.0 10.8 10.7 01-02 3.0-5.0 (j) member of vdB-RN92, (X) 67x 30 2.1 $\pm$ 1.0 2.2 30.35 7 03 52.5 -11 26 17 16.0 1.4 13.7 12.9 12.6 ?? ?? (X) 68j 30 2.0 $\pm$ 1.0 2.1 30.34 7 03 54.0 -11 32 37 14.1 2.3 14.6 13.7 13.3 2-5 0.5-1.0 (j) member of vdB-RN92, 69h 30 7.9 $\pm$ 1.6 4.9 30.93 7 03 54.4 -11 28 29 9.4 1.5 9.4 9.4 9.4 <1? >5 (h) BD -111762 (B2), C 77, SEI 92 70 30 2.2 $\pm$ 1.0 2.2 30.37 7 03 54.8 -11 42 37 15.1 0.3 12.0 11.5 11.3 01-02 1.5-2.0 71x 30 4.9 $\pm$ 1.3 3.7 30.72 7 03 55.7 -11 29 32 14.9 2.5 12.9 12.2 12.0 02-05 1.5-2.0 (X) 72i,j 30 1.6 $\pm$ 0.9 1.9 30.25 7 03 56.8 -11 34 42 11.0 7.0 10.5 10.2 10.1 ?? ?? (i) C 14, SEI 94, (j) member of vdB-RN92, 73j,x 30 2.9 $\pm$ 1.1 2.7 30.50 7 04 00.4 -11 34 00 12.7 7.0 12.1 10.9 10.2 <1 2.0-3.0 (j) member of vdB-RN92, (X) 74*,k 30 9.2 $\pm$ 1.8 5.3 31.00 7 04 01.4 -11 23 35 12.6 2.5 11.5 10.8 10.3 02-05 2.0-3.0 (IRx), (k) member of BRC 27. 75k,l,x 30 6.4 $\pm$ 1.5 4.3 30.84 7 04 02.3 -11 25 39 10.8 1.3 10.4 10.3 10.3 1-2 3.0-5.0 (k) member of BRC 27, (l) SEI 99, (X) 76m 30 3.8 $\pm$ 1.3 3.0 30.61 7 04 06.6 -11 18 35 10.9 6.0 13.1 12.2 11.6 02-05 2.0-3.0 (m) member of NGC 2327 77m 30 3.0 $\pm$ 1.1 2.7 30.51 7 04 09.2 -11 30 08 14.2 0.8 13.7 13.0 12.9 01-02 1.0-1.5 (m) member of NGC 2327 78 30 2.2 $\pm$ 1.2 1.9 30.38 7 04 11.3 -11 16 48 13.4 3.5 12.0 11.4 11.1 05-10 2.0-3.0 79 30 4.1 $\pm$ 1.3 3.2 30.64 7 04 12.1 -11 21 10 13.8 2.9 14.4 13.4 13.1 ?? ?? 80 30 2.1 $\pm$ 1.0 2.1 30.36 7 04 12.3 -11 39 23 12.0 1.2 11.3 11.0 11.0 05-10 2.0-3.0 81m,n 30 3.2 $\pm$ 1.2 2.7 30.54 7 04 13.2 -11 19 01 7.8 3.5 10.9 10.6 10.5 01-02 3.0-5.0 (m) member of NGC 2327, (n) SEI 111 82o,x 30 3.8 $\pm$ 1.2 3.0 30.61 7 04 15.9 -11 24 06 9.4 1.4 9.0 8.9 8.9 <1? >5 (o) HD 53339 (B3), C84, SEI114; (X) 83p 30 3.5 $\pm$ 0.8 4.3 30.58 7 04 17.4 -11 43 10 10.9 0.6 10.2 10.1 10.0 02-05 3.0-5.0 (p) HD 53396 (B9), SEI 112 84x 30 3.5 $\pm$ 0.8 4.3 30.58 7 04 18.3 -11 42 36 13.8 0.0 12.0 11.5 11.3 02-05 1.5-2.0 (X) 85 30 4.2 $\pm$ 1.3 3.3 30.66 7 04 18.8 -11 24 47 14.7 0.8 14.6 13.9 13.7 05-10 0.5-1.0 86x 30 2.9 $\pm$ 1.1 2.6 30.50 7 04 19.1 -11 33 48 13.4 0.4 13.1 12.4 12.2 02-05 0.5-1.0 (X) 87 30 3.0 $\pm$ 1.2 2.6 30.51 7 04 20.0 -11 22 22 13.2 0.9 14.4 13.3 12.7 ?? ?? 88 30 1.8 $\pm$ 0.9 1.9 30.29 7 04 20.6 -11 36 44 16.7 0.7 14.6 13.7 13.5 ?? ?? 89x 30 3.5 $\pm$ 1.2 2.9 30.57 7 04 26.3 -11 31 21 13.8 0.8 12.5 11.6 11.2 ?? ?? (X) 90 30 4.0 $\pm$ 1.3 3.1 30.63 7 04 25.3 -11 34 28 13.2 1.1 11.7 11.1 10.9 <1 1.5-2.0 91x 30 5.2 $\pm$ 1.7 3.1 30.75 7 04 29.8 -11 47 21 12.1 0.0 11.2 10.5 10.3 ?? ?? (X) 92x 30 2.3 $\pm$ 1.1 2.2 30.39 7 04 31.0 -11 32 42 14.0 0.8 13.9 13.1 12.9 01-02 0.1-0.5 (X) 93 30 2.8 $\pm$ 1.1 2.4 30.47 7 04 37.0 -11 30 59 14.0 0.0 14.0 13.8 13.7 ?? ?? 94 30 1.6 $\pm$ 1.0 1.5 30.23 7 04 48.4 -11 15 07 15.7 0.4 14.8 14.4 14.1 >50 1.0-1.5 95 30 5.4 $\pm$ 1.8 3.0 30.76 7 04 52.5 -11 38 21 14.7 0.2 13.2 12.4 12.1 ?? ?? 96x 30 3.4 $\pm$ 1.5 2.3 30.56 7 04 56.3 -11 29 33 12.5 1.2 11.5 10.9 10.2 01-02 2.0-3.0 (X) 97 30 0.9 $\pm$ 0.6 1.7 30.00 7 05 15.5 -11 31 06 14.8 0.0 13.2 12.8 12.7 20-50 1.0-1.5 98 30 0.9 $\pm$ 0.6 1.7 30.00 7 05 15.7 -11 32 05 14.4 0.0 12.8 12.1 12.0 01-02 1.0-1.5 Columns description: (1) Source name: CMaX 1 to 56 (Field 1), CMaX 62 to 98 (Field 2), CMaX 57 to 61 (both fields); (2-5) X-ray data; (6, 7) Coordinates of the optical counterpart, when available; (8, 9) R magnitude and visual extinction (AV), obtained from available catalogues; (10-12) Near-IR magnitudes from the 2MASS catalogue; (13, 14) The estimation of age and mass is based on near-IR. Notes: Stars previously identified (Clariá 1974, indicated by ``C and Shevchenko et al. 1999, indicated by ``SEI'') Objects detected by XMM-Newton and/or Chandra are indicated by ``x''. Relevant sources: (*) H-K excess. Notes: Stars previously identified (Clariá 1974, indicated by ``C'' and Shevchenko et al. 1999, indicated by ``SEI''):