Collinder 135 and UBC 7

• Verfasst von: Kovaleva, Dana A. [VerfasserIn]
• Verfasst von: Ishchenko, Marina [VerfasserIn]
• Verfasst von: Postnikova, Ekaterina [VerfasserIn]
• Verfasst von: Berczik, Peter [VerfasserIn]
• Verfasst von: Piskunov, Anatoly E. [VerfasserIn]
• Verfasst von: Kharchenko, Nina V. [VerfasserIn]
• Verfasst von: Polyachenko, Evgeny [VerfasserIn]
• Verfasst von: Reffert, Sabine [VerfasserIn]
• Verfasst von: Sysoliatina, Kseniia [VerfasserIn]
• Verfasst von: Just, Andreas [VerfasserIn]
• Titel: Collinder 135 and UBC 7
• Titelzusatz: a physical pair of open clusters
• Verf.angabe: Dana A. Kovaleva, Marina Ishchenko, Ekaterina Postnikova, Peter Berczik, Anatoly E. Piskunov, Nina V. Kharchenko, Evgeny Polyachenko, Sabine Reffert, Kseniia Sysoliatina, and Andreas Just
• E-Jahr: 2020
• Jahr: 02 October 2020
• Fussnoten: Gesehen am 11.11.2020
• Titel Quelle: Enthalten in: Astronomy and astrophysics
• Ort Quelle: Les Ulis : EDP Sciences, 1969
• Jahr Quelle: 2020
• Band/Heft Quelle: 642(2020) Artikel-Nummer L4, 5 Seiten
• ISSN Quelle: 1432-0746
• DOI: doi:10.1051/0004-6361/202039215
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1738417956

Abstract

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%.