CCD $UBV(RI)_{KC}$ photometry and dynamics of the open cluster NGC 1513

TL;DR

This study provides detailed photometric and dynamical analysis of the open cluster NGC 1513, determining its age, distance, metallicity, and internal structure, and discusses its dynamical state and evolution.

Contribution

It presents new CCD $UBV(RI)_{KC}$ photometry and comprehensive analysis of NGC 1513's parameters, including age, metallicity, and dynamical state, with comparisons to Gaia data.

Findings

Age of 224±27 Myr for NGC 1513

Distance of approximately 1514±105 pc from the Sun

Evidence of small mass segregation and steep mass function slope

Abstract

We derive astrophysical parameters of the open cluster NGC 1513 by means of colour indices built with new $CCD\,UBV(RI)_{KC}$ photometry. Based on early-type members, the mean foreground reddening and total to selective extinction ratio are E(B-V)=0.79$\pm$0.09 mag and $R_{V}$=2.85$\pm$0.05. Through the differential grid method, we derive the metal abundance [Fe/H]=-0.06 dex (Z=+0.013), which is consistent with the value [Fe/H]=-0.088 of the bright giant member-LAMOST-695710060. The Z=+0.013 isochrone fit to the V x (B-V) colour-magnitude diagram leads to a turn-off age of 224$\pm$27 Myr (thus an intermediate-age cluster), and a distance modulus of ($V_{0}$ - $M_{\rm V}$)=10.90$\pm$0.15 mag, thus implying a distance from the Sun d=1514$\pm$105 pc. Within the uncertainties, our photometric distance is consistent with the value d=1435$\pm$14 pc from the Gaia DR3 parallax. We find signs of small mass segregation through a minimum spanning tree analysis for the 190 most massive stars, together with the rather steep mass function ($\chi$=+2.39) slope. The high core to half-light radius ratio $R_{core}$/$R_{h}$=0.82, together with the compact half-light to tidal radius ratio $R_{h}$/$R_{t}$=0.22, suggest that it is probably related to cluster-formation effects, due to little dynamical evolution, instead of driving its dynamical evolution by internal relaxation. Indeed, NGC 1513 is located in the second quadrant ($\ell$=152.59$^{\circ}$ and Galactocentric distance $R_{GC}$=9.57 kpc), which tends to minimize tidal effects by external processes and tidal disruption. Therefore, internal mass segregation effects in NGC 1513 seem to be more efficient than cluster evaporation processes. We find that NGC 1513 migrated about 0.50 kpc from its birth place.