Double or binary: on the multiplicity of open star clusters

Abstract

Observations indicate that the fraction of potential binary star clusters in the Magellanic Clouds is about 10%. In contrast, it is widely accepted that the binary cluster frequency in the Galaxy disk is much lower. Here we investigate the multiplicity of clusters in the Milky Way disk to either confirm or disprove this dearth of binaries. We quantify the open cluster multiplicity using complete, volume-limited samples from WEBDA and NCOVOCC. At the Solar Circle, at least 12% of all open clusters appear to be experiencing some type of interaction with another cluster; i.e., are possible binaries. As in the Magellanic Clouds, the pair separation histogram hints of a bimodal distribution. Nearly 40% of identified pairs are probably primordial. Most of the remaining pairs could be undergoing some type of close encounter, perhaps as a result of orbital resonances. Confirming early theoretical predictions, the characteristic time scale for destruction of bound pairs in the disk is 200 Myr or one galactic orbit. Our results show that the fraction of possible binary clusters in the Galactic disk is comparable to that in the Magellanic Clouds.

6 pages, 3 figures; accepted by Astronomy and Astrophysics Letters

References in corpus (3)

• On the current status of open-cluster parameters
• Phase Space Structure in the Solar Neighbourhood
• The evolution of binary star clusters and the nature of NGC2136/NGC2137

Cited by in corpus (43)

• Hunting for Neighboring Open Clusters with Gaia DR3: 101 New Open Clusters within 500 pc
• Hierarchical Star Formation in Nearby LEGUS Galaxies
• The Imprint of Cosmic Web Quenching on Central Galaxies
• Tracing the Galactic spiral structure with embedded clusters
• The Evolution of Primordial Binary Open Star Clusters: Mergers, Shredded Secondaries and Separated Twins
• The Villafranca catalog of Galactic OB groups: I. Systems with O2-O3.5 stars
• Dynamical evolution of star-forming regions: III. Unbound stars and predictions for Gaia
• Disruption of Hierarchical Clustering in the Vela OB2 Complex and the Cluster Pair Collinder 135 and UBC7 with Gaia EDR3: Evidence of Supernova Quenching
• Characterizing dynamical states of Galactic open clusters with Gaia DR2
• Star Formation Patterns and Hierarchies
• Characterizing low contrast Galactic open clusters with GAIA DR2
• Binary open clusters in the Gaia data
• The list of possible double and multiple open clusters between galactic longitudes 240 and 270 degrees
• How do binary clusters form?
• Collinder 135 and UBC 7: A Physical Pair of Open Clusters
• Constraining the initial conditions of NGC 2264 using ejected stars found in Gaia DR2
• Investigating Galactic binary cluster candidates with Gaia EDR3
• Revised estimates of CMB $B$-mode polarization induced by patchy reionization
• Binary and Grouped Open Clusters: A New Catalogue
• Pearls on a String: Numerous Stellar Clusters Strung along the Same Orbit
• Discovery and description of two young open clusters in the primordial group of NGC 6871
• Lagrangian theory of structure formation in relativistic cosmology. VI. Comparison with Szekeres exact solutions
• Global properties, fractality, and mass segregation in single, paired, and grouped open clusters
• The Formation of Binary Star Clusters in the Milky Way and Large Magellanic Cloud
• NGC1605a and b: an old binary open cluster in the Galaxy
• A study of newly discovered close binary open clusters in the Milky Way
• The Nature and Nurture of Star Clusters
• Three candidate double clusters in the LMC: truth or dare?
• Revisit of open clusters UPK 39, UPK 41 and PHOC 39 : a new binary open cluster found
• Exploring Galactic open clusters with Gaia I. An examination in the first kiloparsec
• Cluster aggregates surrounding Pismis 5 in the Vela Molecular Ridge
• On the assessment of the nature of open star clusters and the determination of their basic parameters with limited data
• Insights into the properties of the Local (Orion) spiral arm. NGC 2302: First results and description of the program
• Unveiling the Binary Nature of NGC 2323
• Star-by-star dynamical evolution of the physical pair of the Collinder 135 and UBC 7 open clusters
• Beyond relativistic Lagrangian perturbation theory. I. An exact-solution controlled model for structure formation
• On the Encounter Rate of Open Star Clusters
• The Implementation of Binned Kernel Density Estimation to Determine Open Clusters' Proper Motions: Validation of the Method
• A kinematic and structural study of young open clusters in the Milky Way Galaxy using Gaia DR3 catalogue
• Open Cluster Evolutions in Binary System: How They Dissolved
• First evidence of a collision between two unrelated open clusters in the Milky Way
• Deviations from the universal Initial Mass Function in binary star clusters
• Missing pairs in open cluster catalogs