BVRIJHK photometry and proper motion analysis of NGC 6253 and the surrounding field

TL;DR

This study provides a comprehensive photometric and astrometric catalog of stars around NGC 6253, refining its fundamental parameters, analyzing its stellar population, and assessing cluster membership using multi-band data and proper motion analysis.

Contribution

The paper presents new optical and near-infrared photometry combined with proper motion data to refine the properties and membership of NGC 6253, including its age, reddening, and binary fraction.

Findings

Refined cluster distance modulus and reddening values.

Estimated age of NGC 6253 at 3.5 Gyr, slightly older than previous estimates.

Identified 11 blue straggler candidates and a binary fraction of 20-30%.

Abstract

Context. We present a photometric and astrometric catalog of 187963 stars located in the field around the old super-metal-rich Galactic open cluster NGC 6253. The total field-of-view covered by the catalog is 34' x 33'. In this field, we provide CCD BVRI photometry. For a smaller region close to the cluster's center, we also provide near-infrared JHK photometry. Aims. We analyze the properties of NGC 6253 by using our new photometric data and astrometric membership. Methods. In June 2004, we targeted the cluster during a 10 day multi-site campaign, which involved the MPG/ESO 2.2m telescope with its wide-field imager and the Anglo-Australian 3.9m telescope, equipped with the IRIS2 near-infrared imager. Archival CCD images of NGC 6253 were used to derive relative proper motions and to calculate the cluster membership probabilities. Results. We have refined the cluster's fundamental parameters, deriving (V_0-M_v)=11.15, E(B - V)=0.15, E(V - I)=0.25, E(V - J)=0.50, and E(V - H)=0.55. The color excess ratios obtained using both the optical and near infrared colors indicate a normal reddening law in the direction of NGC 6253. The age of NGC 6253 at 3.5 Gyr, determined from our best-fitting isochrone appears to be slightly older than the previous estimates. Finally, we estimated the binary fraction among the cluster members to be \sim20%-30% and identified 11 blue straggler candidates.