J/A+A/693/A305 Open cluster dissolution rate (Almeida+, 2025)
Open cluster dissolution rate and the initial cluster mass function in the
solar neighbourhood. Modelling the age and mass distributions of clusters
observed by Gaia.
Almeida D., Moitinho A., Moreira S.
<Astron. Astrophys. 693, A305 (2025)>
=2025A&A...693A.305A 2025A&A...693A.305A (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Surveys ; Clusters, open ; Optical ; Morphology
Keywords: Galaxy: kinematics and dynamics -
open clusters and associations: general - solar neighborhood
Abstract:
The dissolution rate of open clusters (OCs) and integration of their
stars into the Milky Way's field population has been previously
explored using their age distribution. With the advent of the Gaia
mission, we have an exceptional opportunity to revisit and enhance
these studies with ages and masses from high quality data.
To build a comprehensive Gaia-based OC mass catalogue which, combined
with the age distribution, allows a deeper investigation of the
disruption experienced by OCs within the solar neighbourhood.
Masses were determined by comparing luminosity distributions to
theoretical luminosity functions. The limiting and core radii of the
clusters were obtained by fitting the King function to their observed
density profiles. We examined the disruption process through
simulations of the build-up and mass evolution of a population of OCs
which were compared to the observed mass and age distributions.
Our analysis yielded an OC mass distribution with a peak at
log(M)=2.7dex (∼500M☉), as well as radii for 1724 OCs. Our
simulations showed that using a power-law Initial Cluster Mass
Function (ICMF) no parameters were able to reproduce the observed mass
distribution. Moreover, we find that a skew log-normal ICMF provides a
good match to the observations and that the disruption time of a
104M☉ OC is t4tot=2.9±0.4Gyr.
Our results indicate that the OC disruption time t4tot is about
twice longer than previous estimates based solely on OC age
distributions. We find that the shape of the ICMF for bound OCs
differs from that of embedded clusters, which could imply a low
typical star formation efficiency of ≤20% in OCs. Our results also
suggest a lower limit of ∼60M☉ for bound OCs in the solar
neighbourhood.
Description:
In this study, we determined King and core radii for 1724 open
clusters in the catalogue of Dias et al. (2021MNRAS.504..356D 2021MNRAS.504..356D) as well
as luminous masses which are presented here with their associated
uncertainties. The clusters are classified according to the (visual)
quality of the radii and mass fits as well as dispersion of the
cluster sequence and on the quality of the isochrone match in the CMD.
The cluster center coordinates, age, distance and AV come from the
Dias et al. (2021MNRAS.504..356D 2021MNRAS.504..356D) catalogue.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
clusters.dat 173 1724 Main catalogue (table 4)
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See also:
J/MNRAS/504/356 : Updated parameters of 1743 open clusters (Dias+, 2021)
Byte-by-byte Description of file: clusters.dat
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Bytes Format Units Label Explanations
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1- 17 A17 --- Name Cluster name
19- 23 F5.2 pc Rc Core radius
25- 30 F6.2 pc e_Rc [] Lower uncertainty of Rc
32- 36 F5.2 pc E_Rc Upper uncertainty of Rc
38- 42 F5.2 pc Rk King radius
44- 49 F6.2 pc e_Rk [] Lower uncertainty of Rk
51- 55 F5.2 pc E_Rk Upper uncertainty of Rk
57- 63 F7.1 Msun MassRk Mass in G band, within the King radius
65- 69 F5.1 Msun e_MassRk Uncertainty of MRk
71 A1 --- Mflag [123X] Mass determination flag (1)
73 I1 --- Pflag [1/3] Photometric flag (2)
75 I1 --- Rflag [1/4] King profile fit flag (3)
77- 84 F8.4 deg RAdeg Cluster center right ascension (ICRS) at
Ep=2015.5
86- 93 F8.4 deg DEdeg Cluster center declination (ICRS) at
Ep=2015.5
95- 99 F5.3 [yr] logAge Cluster age
101-105 F5.3 [yr] e_logAge rms uncertainty on logAge
107-110 I4 pc Dist Cluster distance
112-115 I4 pc e_Dist rms uncertainty on Dist
117-121 F5.3 mag AV Absorption in V band
123-127 F5.3 mag e_AV rms uncertainty on AV
129-134 F6.4 pc-2 c Background density
136-142 F7.4 pc-2 e_c [] Lower uncertainty of c
144-149 F6.4 pc-2 E_c Upper uncertainty of c
151-156 F6.2 --- n0 Scaling factor
158-164 F7.2 --- e_n0 [] Lower uncertainty of n0
166-171 F6.2 --- E_n0 Upper uncertainty of n0
173 I1 --- Sample [0/2]? Assigned sample(s) (4)
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Note (1): Classification according to the quality of the mass determination
as follows:
1 = good fit
2 = intermediate fit
3 = worst fit
X = mass determination is invalid due to poor quality CMD
Note (2): Classification according to the dispersion of the cluster sequence
and the quality of the isochrone match in the CMD as follows:
1 = good fit
3 = intermediate fit
3 = worst fit
Note (3): Classification according to the quality of the radii determination
as follows:
1 = best fit
2 = intermediate fit
3 = worst fit
4 = non-reliable
Note (4): Assigned sample based on the overall quality of the 3 fits
as follows:
2 = gold sample
1 = silver sample
0 = full sample
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Acknowledgements:
Duarte Almeida, duarte.almeida(at)sim.ul.pt
(End) Duarte Almeida [Lisbon Univ.], Patricia Vannier [CDS] 18-Dec-2024