Collinder 135 and UBC 7: a physical pair of open clusters

Given the closeness of the two open clusters Collinder 135 and UBC 7 on the sky, we investigate the possibility that the two clusters are physically related. We aim to recover the present-day stellar membership in the open clusters Cr 135 and UBC 7 (300 pc from the Sun) in order to constrain their k...

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Hauptverfasser: Kovaleva, Dana A. (VerfasserIn) , Ishchenko, Marina (VerfasserIn) , Postnikova, Ekaterina (VerfasserIn) , Berczik, Peter (VerfasserIn) , Piskunov, Anatoly E. (VerfasserIn) , Kharchenko, Nina V. (VerfasserIn) , Polyachenko, Evgeny (VerfasserIn) , Reffert, Sabine (VerfasserIn) , Sysoliatina, Kseniia (VerfasserIn) , Just, Andreas (VerfasserIn)
Dokumenttyp: Article (Journal) Editorial
Sprache:Englisch
Veröffentlicht: 02 October 2020
In: Astronomy and astrophysics
Year: 2020, Jahrgang: 642
ISSN:1432-0746
DOI:10.1051/0004-6361/202039215
Online-Zugang:Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1051/0004-6361/202039215
Verlag, lizenzpflichtig, Volltext: https://www.aanda.org/articles/aa/abs/2020/10/aa39215-20/aa39215-20.html
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Verfasserangaben:Dana A. Kovaleva, Marina Ishchenko, Ekaterina Postnikova, Peter Berczik, Anatoly E. Piskunov, Nina V. Kharchenko, Evgeny Polyachenko, Sabine Reffert, Kseniia Sysoliatina, and Andreas Just
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Zusammenfassung:Given the closeness of the two open clusters Collinder 135 and UBC 7 on the sky, we investigate the possibility that the two clusters are physically related. We aim to recover the present-day stellar membership in the open clusters Cr 135 and UBC 7 (300 pc from the Sun) in order to constrain their kinematic parameters, ages, and masses and to restore their primordial phase space configuration. Methods. The most reliable cluster members are selected with our traditional method modified for the use of Gaia DR2 data. Numerical simulations use the integration of cluster trajectories backwards in time with our original high-order Hermite4 code φ−GRAPE. Results. We constrain the age, spatial coordinates, velocities, radii, and masses of the clusters. We estimate the actual separation of the cluster centres equal to 24 pc. The orbital integration shows that the clusters were much closer in the past if their current line-of-sight velocities are very similar and the total mass is more than seven times larger than the mass of the most reliable members. Conclusions. We conclude that the two clusters Cr 135 and UBC 7 might very well have formed a physical pair based on the observational evidence as well as numerical simulations. The probability of a chance coincidence is only about 2%.
Beschreibung:Gesehen am 11.11.2020
Beschreibung:Online Resource
ISSN:1432-0746
DOI:10.1051/0004-6361/202039215