Investigation of open clusters based on IPHAS and APASS survey data

TL;DR

This paper presents a new method combining the Q-method and maximum-likelihood estimation to determine extinction, distances, and ages of young open clusters using IPHAS and APASS survey data, validated against known clusters.

Contribution

It adapts existing techniques for the IPHAS survey data and accounts for variable extinction, enabling more accurate cluster parameter estimation and discovery of new clusters.

Findings

Good agreement with previous extinction and distance estimates

Individual extinction can be accurately determined for certain stars

Method facilitates uniform parameter determination for northern clusters

Abstract

We adapt the classical Q-method based on a reddening-free parameter constructed from three passband magnitudes to thwe filter set of IPHAS survey and combine it with the maximum-likelihood-based cluster parameter estimator by Naylor and Jeffries (2006) to determine the extinction, heliocentric distances, and ages of young open clusters using Halpha and ri data. Themethod is also adapted for the case of signific ant variations of extinction across the cluster rfield. Our technique is validated by comparing the colour excesses, disdtances, and ages determined in this study with the most bona fide values reported for the 18 well-studied young open clusters in the past, and a fairly good agreement is found between our extinction and distance estimnates and earlier published results. although our age estimates are not very consistent with those published by other authors. We also show that individual extinction values can be determined rather accurately for stars with (r-i)0>0.1. Our results open up a prospect fpr determining a uniform set of parameters for northern clusters based on homogeneous photometric data, and for searching for new, hitherto undiscovered open clusters.