J/A+AS/113/419 Proper motions in Praesepe (Wang+ 1995) ================================================================================ High-precision study of proper motions and membership of 924 stars in the central region of Praesepe. WANG J.J., CHEN L., ZHAO J.H., JIANG P.F. =1995A&AS..113..419W ================================================================================ Keywords: astrometry - open clusters, individual: Praesepe Abstract: High-precision proper motions for 257 and 296 stars in a 90x90' region centered on BD+20 2170 were obtained from seven plates taken with the 40cm refractor (f=6895mm) at Zo-Se station of Shanghai Observatory with six AC plates and the stellar positions in Russell's (1976, Ph.D. Thesis, University of Pittsburgh) catalogue, respectively. Combining with the data given by Klein-Wassink, Jones (1971), Artyukhina, and Jones & Cudworth, these proper motions give a sample of 924 stars in the region mentioned above. With membership probabilities estimated by an improved maximum likelihood method, a very good sample of 198 members is obtained with proper motion accuracies ranging from +/-0.2 to +/-5.0mas/yr, of which 60 per cent are better than +/-1.0mas/yr, and the completeness nearly down to B=15.5. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table8 101 924 Combined data of proper motions for 924 stars in the central region of the Praesepe and their membership -------------------------------------------------------------------------------- Byte-by-byte Description of file: table8 -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 2- 4 A3 --- Number Ordinal number 6- 8 A3 --- NRuss Russell's (1976) number 10- 13 A4 --- NKW ? Klein-Wassink's (1927) number 15- 17 A3 --- NArt ? Artyukhina's (1971) number 19- 21 A3 --- NJC ? Jones & Cudworth's (1983) number 24 A1 --- n_Number AC star is indicated with '*' 27- 31 F5.2 mag Mag V magnitude or B magnitude when there is a 'B' in the next column 32 A1 --- n_Mag When 'B' given magnitude is B magnitude 33- 37 F5.2 mag B-V ? B-V colour index 39 A1 --- 1Remarks Remarks: see Note (1) 40 A1 --- 2Remarks Remarks: see Note (2) 41 A1 --- 3Remarks Remarks: see Note (3) 43 I1 h RAh Right ascension for the equinox J2000.0 and epoch 1986.17 45- 46 I2 min RAm Right ascension for the equinox J2000.0 and epoch 1986.17 48- 53 F6.3 s RAs Right ascension for the equinox J2000.0 and epoch 1986.17 55 A1 --- DE- Declination sign 56- 57 I2 deg DEd Declination for the equinox J2000.0 and epoch 1986.17 59- 60 I2 arcmin DEm Declination for the equinox J2000.0 and epoch 1986.17 62- 66 F5.2 arcsec DEs Declination for the equinox J2000.0 and epoch 1986.17 69- 72 I4 0.1mas/yr pmRA Proper motion component in right ascension reduced into the great circle 74- 76 I3 0.1mas/yr e_pmRA Standard error of proper motion in RA 78- 82 I5 0.1mas/yr pmDE Proper motion component in declination 84- 86 I3 0.1mas/yr e_pmDE Standard error of proper motion in DE 88- 91 F4.2 --- Prob Membership probability 93 I1 --- Member Membership judgement:'1' if probability is less than 0.36, '0' otherwise 95-100 A6 --- n_Member Notes about previous membership judgements, note (4) -------------------------------------------------------------------------------- Note (1): P - photoelectric G - photographic Note (2): C - combined from Johnson(1952), Upgren et al.(1979), Weis(1981), and Stauffer(1982) G - Gotz's (1984) J - Jones & Cudworth's (1983) R - Russell's (1976) Note (3): B - s.e. less than 0.01 G - s.e. from 0.01 to 0.04 F - s.e. from 0.04 to 0.08 P - s.e. greater than 0.08 Note (4): K - member by Klein-Wassink (1927) A - member by Artyukhina (1971) Figures - non-zero membership probability by Jones & Cudworth (1983) -------------------------------------------------------------------------------- References: Artyukhina N.M. 1971, Soobshch.Gos.Astron.Inst.Sternberga 172, 3 =1971SoSht.172....3A Gotz W. 1984, AN 305, 17 =1984AN....305...17G Johnson H.L. 1952, ApJ 116, 640 =1952ApJ...116..640J Jones B.F., Cudworth K. 1983, AJ 88, 215 =1983AJ.....88..215J Klein-Wassink W.J. 1927, Groningen Publ. 41 =1927PGro...41....1K Russell J.L. 1976, Ph.D. Thesis, University of Pittsburgh Stauffer J. 1982, PASP 94, 678 =1982PASP...94..678S Upgren A.R., Weis E.W., DeLuca E.E. 1979, AJ 84, 1586 =1979AJ.....84.1586U Weis E.W. 1981, PASP 93, 437 =1981PASP...93..437W -------------------------------------------------------------------------------- Courtesy: Wang Jiaji ================================================================================ (End) Simona Mei [CDS] 21-Nov-1995