Physical properties of globular clusters NGC 288 and NGC 362 from the ACS survey of the Hubble Space Telescope

This research aims to study the physical properties of two interesting globular clusters NGC 288 and NGC 362, considering photometric data in the visible (V) and infrared (I) bands. The study utilizes archival data collected from the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS). The data for these two globular clusters (GCs) were collected by using F606W (V) and F814W (I) bands. Data reduction and calibration were performed using the ACS pipeline, and photometry was conducted using the DOLPHOT software package. New theoretical isochrone fitting to the color-magnitude diagram (CMD) of both globular clusters were analysed using PAdova and the TRieste Stellar Evolution Code (PARSEC) in version 1.2S, which is an appropriate tool for estimating age, metallicity, and distance of stellar clusters and modeling the evolutionary stage of stellar clusters. The total exposure times were 4x130s in F606W, 4x150s in F814W for NGC 288, and 4x150s in F606W, 4x170s in F814W for NGC 362. We used photometric data from the ACS survey to construct a CMD and fitted isochrone lines to determine the physical properties of these globular cluster samples. We obtained the following characteristics for NGC 288 and NGC 362, respectively; metallicities [Fe/H] = -1.30 +/- 0.05 dex for both clusters; ages 13.0 +/- 0.5 Gyr and 11.0 +/- 0.5 Gyr; distance modulus (m - M) = 14.91 +/- 0.01 and 14.90 +/- 0.01; reddening E(V - I) = 0.01 mag and 0.02 mag. This study focuses on up-to-date theoretical stellar evolution models for these two globular clusters. The new stellar evolutionary model provides a more accurate value of distance, age, metallicity, extinction, and evolutionary stage of cluster members.