Determination of dynamical ages of open clusters through the A+ parameter – I

The sedimentation level of blue straggler stars (BSS) has been shown to be a great tool investigate the dynamical states globular clusters (GCs). area enclosed between cumulative radial distributions BSS and reference population up half-mass radius clusters, $A^+_{\mathrm{rh}}$, is known measure in GCs. In this work, we calculate $A^+_{\mathrm{rh}}$ for 11 open (OCs) using combined list main-sequence turn-off stars, sub-giant branch red-giant as population. BSS, populations, cluster members are identified proper motions parallaxes from Gaia DR2 data. subset confirmed on basis velocity information available literature. Using Pearson Spearman rank correlation coefficients, find weak correlations estimated values other markers ages i.e., number central relaxations experienced since its formation, structural parameters clusters. Based statistical tests, that these similar corresponding among less evolved GCs, albeit within large errors.