Characterizing dynamical stages of open clusters located in the Sagittarius spiral arm

M.S. ANGELO, A.E. PIATTI, W.S. DIAS, F.F.S. MAIA

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2019 vol. 488 p. 1635 - 1651

0035-8711

The study of dynamical properties of Galactic open clusters is a fundamental pre-requisite for the comprehension of their dissolution processes. In this work, we char-acterized 12 open clusters, namely: Collinder 258, NGC6756, Czernik 37, NGC5381,Ruprecht 111, Ruprecht 102, NGC6249, Basel 5, Ruprecht 97, Trumpler 25, ESO129-SC32 and BH150, projected against dense stellar elds. In order to do that, we em-ployed Washington CT1 photometry and GAIA DR2 astrometry, combined with a de-contamination algorithm applied to the three-dimensional astrometric space of propermotions and parallaxes. From the derived membership likelihoods, we built decontam-inated colour-magnitude diagrams, while structural parameters were obtained fromKing proles tting. Our analysis revealed that they are relatively young open clus-ters (log(t yr􀀀1) 7:3􀀀8:6), placed along the Sagittarius spiral arm, and at dierentinternal dynamical stages. We found that the half-light radius to Jacobi radius ratio,the concentration parameter and the age to relaxation time ratio describe satisfac-torily their dierent stages of dynamical evolution. Those relative more dynamicallyevolved open clusters have apparently experienced more important low-mass star loss