J/A+A/333/897 Mass segregation in open clusters (Raboud+ 1998)
Evolution of mass segregation in open clusters: some observational evidences
Raboud D., Mermilliod J.-C.
<Astron. Astrophys. 333, 897 (1998)>
=1998A&A...333..897R 1998A&A...333..897R
ADC_Keywords: Clusters, open ; Photometry ; Stars, distances ; Stars, masses
Keywords: clusters: open - individual: Praesepe, NGC 6231 - star: formation
Abstract:
On the basis of the best available member list and duplicity
information, we have studied the radial structure of Praesepe and of
the very young open cluster NGC 6231. We have found mass segregation
among the cluster members and between binaries and single stars, which
is explained by the greater average mass of the multiple systems.
However, the degree of mass segregation for stars between 1.5 and
2.3M☉ is less pronounced in Praesepe than in the Pleiades.
Furthermore, mass segregation is already present in the very young
open cluster NGC 6231 although this cluster is likely still not
dynamically relaxed. We discuss the implications of these results and
propose a qualitative scenario for the evolution of mass segregation
in open clusters.
In Praesepe the mass function of single stars and primaries appears to
be significantly different, like in the Pleiades. We observe an
absence of ellipticity of the outer part of Praesepe.
Objects:
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RA (2000) DE Designation(s)
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08 40.4 +19 40 Praesepe = NGC 2632 = M 44
16 54.2 -41 48 NGC 6231
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 74 185 Member stars in Praesepe
table3.dat 82 300 Member stars in NGC 6231
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See also:
J/A+A/325/167 : Geneva photometry in NGC 6231 (Raboud+ 1997)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- KW Star identification
(Cl* NGC 2632 KW NNN in Simbad database)
7- 11 F5.2 mag Vmag V magnitude
14- 17 F4.2 mag B-V B-V colour index
20- 26 F7.2 arcmin Xpos x coordinate (1)
29- 35 F7.2 arcmin Ypos y coordinate (1)
37- 42 F6.2 arcmin Dist Distance from the cluster center
44 I1 --- Mult [1/3] Multiplicity status (G1)
46- 54 A9 --- Type Binary type (G2)
56- 59 F4.2 solMass MassTot Total mass
61- 64 F4.2 solMass MassA Component A mass
66- 69 F4.2 solMass MassB ? Component B mass
71- 74 F4.2 solMass MassC ? Component C mass
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Note (1): Origin (1950.0), RA = 08 37 32 ; DE = +19 48.8
y increasing to North , x to East
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- NGC6231 Star identification
(NGC 6231 NNN in Simbad database)
7- 11 F5.2 mag Vmag V magnitude
14- 18 F5.2 mag col Colour ((B-V)J, (B-V)G or b-y) (1)
21- 24 A4 --- phot Photometry used (Gen, UBV or uvby)
28- 33 F6.2 arcmin Xpos x coordinate (2)
37- 42 F6.2 arcmin Ypos y coordinate (2)
46- 50 F5.2 arcmin Dist Distance from the cluster center
53 I1 --- Mult [1/2] Multiplicity status (G1)
56- 62 A7 --- Type Binary type (G1)
65- 69 F5.2 solMass MassTot Total mass
72- 76 F5.2 solMass MassA ? Component A mass
78- 82 F5.2 solMass MassB ? Component B mass
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Note (1): The colour is
(B-V)(Johnson) if the photometry used (phot column) is UBV,
(B-V)(Geneva) if the photometry used is Gen and
(b-y) if the photometry used is uvby.
Note (2): Origin (1950.0) RA = 16 50 41 ; DE =-41 44.9
y increasing to North , x to East
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Global Notes:
Note (G1): Multiplicity status, defined as follows:
1 = Single
2 = Double
3 = Triple
Note (G2): Binary type, defined as follows:
Occ = Occultation binary
PHB = Photometric binary
SB = Spectroscopic binary
VB = visual binary
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Acknowledgements:
Didier Raboud
(End) Raboud [Geneva Observatory] 20-Feb-1998