J/A+A/624/A8 Evolved Galactic open clusters dynamical properties (Angelo+, 2019)
Investigating dynamical properties of evolved Galactic open clusters.
Angelo M.S., Santos Jr. J.F.C., Corradi W.J.B., Maia F.F.S.
<Astron. Astrophys. 624, A8 (2019)>
=2019A&A...624A...8A 2019A&A...624A...8A (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Populations, stellar ; Photometry, infrared ;
Parallaxes, trigonometric ; Proper motions
Keywords: open cluster and associations: general
Abstract:
The stellar content of Galactic open clusters (OCs) is gradually
depleted during their evolution as a result of internal relaxation and
external interactions. The final residues of the long-term evolution
of OCs are called open cluster remnants (OCRs).These are sparsely
populated structures that can barely be distinguished from the field.
We aimed to characterise and compare the dynamical states of a set of
16 objects catalogued as OCRs or OCR candidates. The sample also
includes 7 objects that are catalogued as dynamically evolved OCs for
comparison purposes. We used photometric data from the 2MASS
catalogue, proper motions and parallaxes from the GAIA DR2 catalogue,
and a decontamination algorithm that was applied to the
three-dimensional astrometric space of proper motions and parallaxes
(µ_α, µ_δ, ϖ) for stars in the objects' areas.
The investigated OCRs present masses (M) and velocity dispersions
(σv) within well-defined ranges: M between ∼10-40M_☉ and
σv between ∼1-7km/s. Some objects in the remnant sample have a
limiting radius Rlim≲2pc, which means that they are more compact
than the investigated OCs; other remnants have Rlim between ∼2-7pc,
which is comparable to the OCs. In general, our clusters show signals
of depletion of low-mass stars. This confirms their dynamically
evolved states. Using results from N-body simulations, we conclude
that the OCRs we studied are in fact remnants of initially very
populous OCs (N0∼103-104stars). The outcome of the long-term
evolution is to bring the final residues of the OCs to dynamical
states that are similar to each other, thus masking out the memory of
the initial formation conditions of star clusters.
Description:
Near-infrared (J, H, and Ks band) photometric data from the 2MASS
catalogue (Skrutskie et al., 2006, Cat. VII/233) and GAIA DR2 (Gaia
Collaboration et al. 2018) astrometric parameters (µ_α,
µ_δ, ϖ) for member stars of 16 objects catalogued as
open cluster remnants or remnant candidates. The sample also contains
data for stars in 7 objects that are catalogued as dynamically evolved
open clusters (see Table 1 of the paper). Member stars were selected
according to the procedure described in Section 3 of the paper. Our
sample also contains 5 objects (namely NGC1252, NGC7772, ESO570-12,
ESO383-SC10, and ESO065-SC03) which were classified as asterisms
(Section 4.2 of the paper). We appended the suffix '_asterism' to
these objects' names in the table.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 116 23 Coordinates and parameters of the studied
open clusters and remnants
clusters.dat 135 1823 Positions, magnitudes (from 2MASS) and astrometric
data (from GAIA DR2) for member stars of each
open cluster or remnant
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See also:
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Type Type of cluster (1)
6- 17 A12 --- Cluster Cluster name
18 A1 --- n_Cluster [ab] Note on Cluster (2)
21- 25 F5.1 deg GLON Galactic longitude
27- 31 F5.1 deg GLAT Galactic latitude
33- 34 I2 h RAh Rigth ascension (J2000)
36- 37 I2 min RAm Rigth ascension (J2000)
39- 40 I2 s RAs Rigth ascension (J2000)
42 A1 --- DE- Declination sign (J2000)
43- 44 I2 deg DEd Declination (J2000)
46- 47 I2 arcmin DEm Declination (J2000)
49- 50 I2 arcsec DEs Declination (J2000)
52- 55 F4.2 kpc dsun Distance from the Sun
57- 60 F4.2 kpc e_dsun rms uncertainty on distance from the Sun
62- 65 F4.1 kpc RG Galactocentric distance
67- 69 F3.1 kpc e_RG rms uncertainty on Galactocentric distance
71- 75 F5.2 kpc ZG Distance from the Galactic plane
77- 80 F4.2 kpc e_ZG rms uncertainty on Distance from the
Galactic plane
82- 85 F4.2 Gyr Age Cluster age
87- 90 F4.2 Gyr e_Age rms uncertainty on Cluster age
92- 96 F5.2 pc Rlim Limiting radius
98-101 F4.2 pc e_Rlim rms uncertainty on Limiting radius
103-105 I3 Msun Mphot Photometric mass
107-108 I2 Msun e_Mphot rms uncertainty on Photometric mass
110-112 F3.1 km/s sigma Velocity dispersion
114-116 F3.1 km/s e_sigma Velocity dispersion
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Note (1): Type as follows:
OCs = Open clusters
OCRs = Open cluster remnants
Note (2): Notes as follows:
a = [Fe/H]=0.12 (Carraro et al., 2014A&A...568A..86C 2014A&A...568A..86C)
b = In this paper, we advocate that this cluster (previously classified as
an OC) is entering a remnant evolutionary stage
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Byte-by-byte Description of file: clusters.dat
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Bytes Format Units Label Explanations
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1- 21 A21 --- Cluster Cluster name (1)
24- 26 I3 --- StarID Star identification within the cluster
28- 37 F10.6 deg RAdeg Right ascension (J2000.0)
39- 48 F10.6 deg DEdeg Declination (J2000.0)
50- 55 F6.3 mag Jmag Magnitude (2MASS J)
57- 61 F5.3 mag e_Jmag Magnitude error (2MASS J)
63- 68 F6.3 mag Hmag Magnitude (2MASS H)
70- 74 F5.3 mag e_Hmag Magnitude error (2MASS H)
76- 81 F6.3 mag Ksmag Magnitude (2MASS Ks)
83- 87 F5.3 mag e_Ksmag Magnitude error (2MASS Ks)
89- 95 F7.4 mas plx ?=- Parallax (GAIA DR2) (2)
97-103 F7.4 mas e_plx ?=- Parallax error (GAIA DR2)
105-112 F8.3 mas/yr pmRA ?=- Proper motion in RA, pmRA*cosDE
(GAIA DR2) (2)
114-119 F6.3 mas/yr e_pmRA ?=- Proper motion error in RA (GAIA DR2)
121-128 F8.3 mas/yr pmDE ?=- Proper motion in DEC (GAIA DR2) (2)
130-135 F6.3 mas/yr e_pmDE ?=- Proper motion error in DEC (GAIA DR2)
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Note (1): The objects NGC1252, NGC7772, ESO570-12, ESO383-SC10, and ESO065-SC03
were classified as asterisms (or non-existent clusters; section 4.2 of the
paper). This objects' names received the suffix '_asterism' in the table.
Note (2): Stars without available astrometric information on GAIA DR2 catalog
received the value '---' in the corresponding columns.
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Acknowledgements:
Mateus Angelo, altecc(at)lilith.fisica.ufmg.br
References:
Skrutskie et al., 2MASS, 2006AJ....131.1163S 2006AJ....131.1163S, Cat. VII/233
Arenou et al., Gaia Data Release 2. Catalogue validation, 2018A&A...616A..17A 2018A&A...616A..17A
Gaia Collaboration, Gaia Data Release 2.
Summary of the contents and survey properties, 2018A&A...616A...1G 2018A&A...616A...1G
(End) Mateus Angelo [CEFET-MG, Brazil], Patricia Vannier [CDS] 22-Feb-2019