J/A+A/659/A59 Structural parameters of 389 local open clusters (Tarricq+, 2022)
Structural parameters of 389 local open clusters.
Tarricq Y., Soubiran C., Casamiquela L., Castro-Ginard A., Olivares, J.,
Miret-Roig N., Galli P.A.B.
<Astron. Astrophys. 659, A59 (2022)>
=2022A&A...659A..59T 2022A&A...659A..59T (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Milky Way ; Parallaxes, trigonometric ;
Proper motions ; Surveys
Keywords: Galaxy: kinematics and dynamics - Galaxy: structure -
methods: statistical - surveys -
open clusters and associations: general
Abstract:
The distribution of member stars in the surroundings of an Open
Cluster (OC) can shed light on the process of its formation, evolution
and dissolution. The analysis of structural parameters of OCs as a
function of their age and position in the Galaxy brings constraints on
theoretical models of cluster evolution. The Gaia catalogue is very
appropriate to find members of OCs at large distance from their
centers. We aim at revisiting the membership lists of OCs from the
solar vicinity, in particular by extending these membership lists to
the peripheral areas thanks to Gaia EDR3. We then take advantage of
these new lists of members to study the morphological properties and
the mass segregation levels of the clusters. We used the clustering
algorithm HDBSCAN on Gaia parallaxes and proper motions to
systematically look for members up to 50pc from the cluster centers.
We fitted a King's function on the radial density profile of these
clusters and a Gaussian Mixture Model (GMM) on their two dimensional
distribution of members to study their shape. We also evaluated the
degree of mass segregation of the clusters and the correlations of
these parameters with the age and Galactic position of the clusters.
Our methodology performs well on 389 clusters out of the 467 selected
ones, including several recently discovered clusters that were poorly
studied until now. We report the detection of vast coronae around
almost all the clusters and report the detection of 71 OCs with tidal
tails, multiplying by more than four the number of such structures
identified. We find the size of the cores to be on average smaller for
old clusters than for young ones. Also, the overall size of the
clusters seems to slightly increase with age while the fraction of
stars in the halo seems to decrease. As expected the mass segregation
is more pronounced in the oldest clusters but a clear trend with age
is not seen. OCs are more extended than previously expected,
regardless of their age. The decrease in the proportion of stars
populating the clusters halos highlights the different cluster
evaporation processes and the short timescales they need to affect the
clusters. Reported parameters like cluster sizes or mass segregation
levels all depend on cluster ages but can not be described as single
functions of time.
Description:
In this paper we compile lists of members at large distances from the
cluster centers for 389 open clusters located closer than 1.5kpc and
younger than 50Myr. We take advantage of these extended lists of
members to study the clusters extension, shape and degree of mass
segregation.
Table 1 contains the 467 clusters from (Cantat-Gaudin+, 2020), older
than 50Myr and closer than 1.5kpc. The mean cluster parameters
determined in this study are reported for 389 of them.
Table 2 contains the members recovered for the 389 clusters studied
here. All columns are from the Gaia EDR3 catalogue, except the
membership probability.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 1081 467 Mean cluster parameters
table2.dat 419 144596 Members
--------------------------------------------------------------------------------
See also:
I/350 : Gaia DR2 (Gaia Collaboration, 2018)
J/A+A/640/A1 : Portrait Galactic disc (Cantat-Gaudin+, 2020)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 17 A17 --- Cluster Cluster name
19- 22 F4.2 [yr] logAgeNN Cluster age (logt) (1)
24- 29 F6.1 pc Dist Distance (1)
31- 34 I4 --- Nstars ? Number of members with proba over 0.5
36- 55 F20.16 deg RAdeg ? Mean Right Ascension (ICRS) at Ep=2016
57- 76 F20.16 deg DEdeg ? Mean Declination (ICRS) at Ep=2016
78- 97 F20.16 mas/yr pmRA ? Mean proper motion along right
ascension: pmRA*cosDE
99- 119 E21.16 mas/yr s_pmRA ? Standard deviation of proper motion in
right ascension
121- 140 F20.16 mas/yr pmDE ? Mean proper motion in Declination
142- 159 F18.16 mas/yr s_pmDE ? Standard deviation of proper motion in
declination
161- 179 F19.16 mas plx ? Mean parallax
181- 198 F18.16 mas s_plx ? Standard deviation of parallax
200- 219 F20.16 deg GLON ? Mean Galactic longitude
221- 240 F20.16 deg GLAT ? Mean Galactic latitude
242- 260 F19.16 pc Rc ? Core radius
262- 280 F19.16 pc Rt ? Tidal radius
282- 301 F20.16 pc e_Rc []? Lower error on Rc
303- 322 F20.16 pc E_Rc []? Upper error on Rc
324- 343 F20.16 pc e_Rt []? Lower error on Rt
345- 363 F19.16 pc E_Rt ? Upper error on Rt
365- 383 A19 --- f_Rc ? Flag on Rc convergence
385- 403 A19 --- f_Rt ? Flag on Rt convergence
405- 422 F18.16 --- b/aCore ? Ratio between semi-minor and
semi-major axis of the core
424- 441 F18.16 --- b/aTail ? Ratio between semi-minor and
semi-major axis of the tail
443- 460 F18.16 --- b/aHalo ? Ratio between semi-minor and
semi-major axis of the halo
462- 479 F18.16 --- WeightCore ? Relative weight of the core
481- 498 F18.16 --- WeightTail ? Relative weight of the tail
500- 517 F18.16 --- WeightHalo ? Relative weight of the halo
519- 538 F20.16 deg AngleCore ? Core orientation with respect to the
Galactic plane
540- 559 F20.16 deg AngleTail ? Tail orientation with respect to the
Galactic plane
561- 580 F20.16 deg AngleHalo ? Halo orientation with respect to the
Galactic plane
582- 600 F19.16 pc aCore ? Semi-major axis of the core
602- 620 F19.16 pc bCore ? Semi-minor axis of the core
622- 639 F18.15 pc aTail ? Semi-major axis of the tail
641- 658 F18.16 pc bTail ? Semi-minor axis of the tail
660- 677 F18.15 pc aHalo ? Semi-major axis of the halo
679- 696 F18.15 pc bHalo ? Semi-minor axis of the halo
698- 719 E22.17 --- e_WeightCore ? Error on weights_core
721- 742 E22.17 --- e_WeightTail ? Error on weights_tail
744- 765 E22.17 --- e_WeightHalo ? Error on weights_halo
767- 788 E22.17 pc e_aCore ? Error on a_core
790- 811 E22.17 pc e_bCore ? Error on b_core
813- 833 E21.16 pc e_aTail ? Error on a_tail
835- 856 E22.17 pc e_bTail ? Error on b_tail
858- 879 E22.17 pc e_aHalo ? Error on a_halo
881- 902 E22.17 pc e_bHalo ? Error on b_halo
904- 925 E22.17 deg e_AngleCore ? Error on angle_core
927- 947 E21.16 deg e_AngleTail ? Error on angle_tail
949- 970 E22.17 deg e_AngleHalo ? Error on angle_halo
972- 993 E22.17 --- e_b/aCore ? Error on axisratiocore
995-1016 E22.17 --- e_b/aTail ? Error on axisratiotail
1018-1039 E22.17 --- e_b/aHalo ? Error on axisratiohalo
1041-1042 I2 --- NstarsSeg ? Number of stars with mass segregation
ratio above 2
1044-1062 F19.16 --- lambda10 ? Mass segregation ratio of the 10th most
massive star
1064-1081 F18.16 --- e_lambda10 ? Error on lambda_10
--------------------------------------------------------------------------------
Note (1): Column coming from (Cantat-Gaudin+, 2020, Cat. J/A+A/640/A1)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 I19 --- GaiaEDR3 Gaia EDR3 source ID
21- 40 F20.16 deg RAdeg Right Ascension (ICRS) at Ep=2016
42- 59 F18.16 mas e_RAdeg Standard error of the right ascension
61- 80 F20.16 deg DEdeg Declination (ICRS) at Ep=2016
82- 99 F18.16 mas e_DEdeg Standard error of the declination
101-119 F19.16 mas plx Absolute stellar parallax
121-138 F18.16 mas e_plx Standard error on parallax
140-160 E21.16 mas/yr pmRA Proper motion in right ascension direction
(pmRA*cosDE)
162-179 F18.16 mas/yr e_pmRA Standard error of pmra
181-202 E22.16 mas/yr pmDE Proper motion in declination
204-221 F18.16 mas/yr e_pmDE Standard error of pmDE
223-245 E23.17 --- plxpmRAcor Correlation between parallax and
proper motion in right ascension
247-269 E23.17 --- plxpmDEcor Correlation between parallax and
proper motion in declination
271-293 E23.17 --- pmRApmDEcor Correlation between proper motion in
right ascension and in declination
295-312 F18.16 --- RUWE Renormalised unit weight error
314-332 F19.16 mag Gmag G-band mean magnitude
334-352 E19.16 mag BP-RP ? BP-RP colour index
354-373 F20.16 deg GLON Galactic longitude
375-396 E22.17 deg GLAT Galactic latitude
398-414 A17 --- Cluster Cluster name
416-419 F4.2 --- Proba Membership probability
--------------------------------------------------------------------------------
Acknowledgements:
Yoann Tarricq, yoann.tarricq(at)u-bordeaux.fr
(End) Patricia Vannier [CDS] 13-Dec-2021