J/A+AS/128/255 Proper motions in M 11 (Su+ 1998)
Membership determination of stars using proper motions in the region
of the open cluster M11
Su C.-G., Zhao J.-L., Tian K.-P.
<Astron. Astrophys. Suppl. Ser. 128, 255 (1998)>
=1998A&AS..128..255S 1998A&AS..128..255S (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Proper motions
Keywords: star cluster: open - star cluster: individual: M11 -
proper motion: membership determination
Abstract:
Relative proper motions of 872 stars in the open cluster M 11 region
are reduced using 10 plate pairs taken over time baselines of 16∼70
years with the double astrograph telescope of Shanghai Observatory.
The scale is 30"/mm. The plates were measured with the PDS machines in
the Purple Mountain Observatory in Nanjing and the Institute of
Technology and Communication in Luoyang, China. The average proper
motion accuracy is about 1.1mas/yr with 85% of the data better than
1mas/yr. Membership probabilities of 785 stars within 25' centred on M
11 are determined based on their proper motions. The method used is
suggested by Su et al. (1995AcApS..15..217S 1995AcApS..15..217S) with some improvements of
Zhao & He (1990A&A...237...54Z 1990A&A...237...54Z), in which the space distribution and
magnitude dependencies for cluster stars are taken into account. The
results are significantly good. The total integrated membership
probabilities for all these stars is 547 and the number of stars with
probabilities higher than 0.7 is 541. It can be found after the
membership determination that there exists mass segregation in M 11.
Some comparisons and discussion are also given.
Objects:
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RA (2000) DE Designation(s)
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18 51.1 -06 16 M 11 = NGC 6705
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 80 872 Relative proper motions and membership
probabilities of stars in the M11 region
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Star Star number
5 A1 --- n_Star [*] *: Reference star
6- 10 I5 --- NSP ? Star number in the catalogue of
McNamara, Pratt & Sanders
(1977A&AS...27..117M 1977A&AS...27..117M)
13- 18 F6.3 cm Xpos Measured coordinate in X (1)
21- 26 F6.3 cm Ypos Measured coordinate in Y (1)
29- 33 F5.2 mag Vmag V magnitude
36- 40 F5.2 mag Bmag ? B magnitude
43- 48 F6.3 10-2arcsec/yr pmX Relative proper motion in X
51- 56 F6.3 10-2arcsec/yr pmY Relative proper motion in Y
59- 63 F5.3 10-2arcsec/yr e_pmX Uncertainty of proper motion in X
66- 70 F5.3 10-2arcsec/yr e_pmY Uncertainly of proper motion in Y
73- 74 I2 --- Nplate Number of the plate pairs
77- 80 F4.2 % Member ? Membership probability
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Note (1): 1 mm = 30"
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Acknowledgements: Tian Kaiping
(End) Francois Ochsenbein [CDS] 15-Jul-1997