Revisiting Some Pismis Open Clusters Using Gaia Environmental Technology

Abstract

In this study, we considered the collective members of Pismis’s clusters located at identical distances r(pc) and distributed around a mean absolute magnitude (M_o) following a Gaussian distribution with dispersion . We computed the distances r_c(pc) of these clusters by applying a distance equation designed to account for Malmquist bias. Our computed distances were in satisfactory agreement  when compared to previous research findings.

In the second part of our work, we delved extensively into the Pismis 3 cluster, which is rarely studied, aged, and among the most affluent. We conducted analyses on its dynamical tidal radius , crossing time , relaxation time , and angular velocity .

A kinematic analysis of these open clusters was carried out, encompassing aspects such as their apex position using the AD chart method, velocity ellipsoid parameters (VEPs), and the longitude of the vertex  revealing a minimal value, as anticipated when pointing exactly at the Galactic Center. Additionally, we explored their ages in relation to evolution, linking them to formation mechanisms, metallicity, and opacity.