# The extended halo of NGC 2682 (M 67) from Gaia DR2 **Authors:** R. Carrera (1), M. Pasquato (1), A. Vallenari (1), L., Balaguer-N\'u\~nez (2), T. Cantat-Gaudin (2), M. Mapelli (1,3,4,5), A., Bragaglia (6), D. Bossini (1,7), C. Jordi (2), D. Galad\'i-Enr\'iquez (8), E., Solano (9) ((1) INAF-Osservatorio Astronomico di Padova, vicolo, dell'Osservatorio 5, 35122 Padova, Italy, (2) Institut de Ci\`encies del, Cosmos, Universitat de Barcelona (IEEC-UB), Mart\'i i Franqu\`es 1, E-08028, Barcelona, Spain, (3) Physics, Astronomy Department Galileo Galilei,, University of Padova, Vicolo dell'Osservatorio 3, I-35122, Padova, Italy, (4), INFN-Padova, Via Marzolo 8, I-35131 Padova, Italy, (5) Institut f\"ur Astro-, und Teilchenphysik, Universit\"at Innsbruck, Technikerstrasse 25/8, A-6020,, Innsbruck, Austria, (6) INAF-Osservatorio di Astrofisica e Scienza dello, Spazio, via P. Gobetti 93/3, 40129 Bologna, Italy, (7) Instituto de, Astrof\'isica e Ci\^encias do Espa\c{c}o, Universidade do Porto, CAUP, Rua, das Estrelas, 4150-762 Porto, Portugal, (8) Observatorio de Calar Alto,, Sierra de los Filabres, E-04550-G\'ergal, Almer\'ia, Spain, (9) Centro de, Astrobiolog\'ia (INTA-CSIC), Departamento de Astrof\'isica. P.O. Box 78,, E-28691, Villanueva de la Ca\~nada, Madrid, Spain, Spanish Virtual, Observatory) arXiv: 1905.02020 · 2019-07-17 ## TL;DR This study uses Gaia DR2 data to map the extended spatial distribution of NGC 2682, revealing it is twice as large as previously thought and providing insights into its dynamical history and external perturbations. ## Contribution It demonstrates a method to identify and analyze the extended halo of an open cluster using Gaia data, revealing a larger size and potential external influences on NGC 2682. ## Key findings - NGC 2682 extends up to 50 pc, twice previous estimates. - The cluster's size exceeds its Hill sphere, indicating ongoing dynamical processes. - External perturbations like disk shocking likely influence the cluster's outskirts. ## Abstract Context: NGC 2682 is a nearby open cluster, approximately 3.5 Gyr old. Dynamically, most open clusters should dissolve on shorter timescales, of ~ 1 Gyr. Having survived until now, NGC 2682 was likely much more massive in the past, and is bound to have an interesting dynamical history. Aims: We investigate the spatial distribution of NGC 2682 stars to constrain its dynamical evolution, especially focusing on the marginally bound stars in the cluster outskirts. Methods: We use Gaia DR2 data to identify NGC 2682 members up to a distance of ~150 pc (10 degrees). Two methods (Clusterix and UPMASK) are applied to this end. We estimate distances to obtain three-dimensional stellar positions using a Bayesian approach to parallax inversion, with an appropriate prior for star clusters. We calculate the orbit of NGC 2682 using the GRAVPOT16 software. Results: The cluster extends up to 200 arcmin (50 pc) which implies that its size is at least twice as previously believed. This exceeds the cluster Hill sphere based on the Galactic potential at the distance of NGC 2682. Conclusions: The extra-tidal stars in NGC 2682 may originate from external perturbations such as disk shocking or dynamical evaporation from two-body relaxation. The former origin is plausible given the orbit of NGC 2682, which crossed the Galactic disk ~40 Myr ago. ## Full text _Full body text omitted from this summary view._ Fetch the complete paper as Markdown: https://tomesphere.com/paper/1905.02020/full.md ## Figures 7 figures with captions in the complete paper: https://tomesphere.com/paper/1905.02020/full.md ## References 59 references — full list in the complete paper: https://tomesphere.com/paper/1905.02020/full.md --- Source: https://tomesphere.com/paper/1905.02020