Insights on the Optical and Infrared Nature of MAXI J0709-159: Implications for High-Mass X-ray Binaries

TL;DR

This study investigates the optical and infrared properties of MAXI J0709-159 and its counterpart HD 54786, revealing dual characteristics and evolutionary insights within high-mass X-ray binaries through CMD analysis and statistical tests.

Contribution

It provides new evidence for the dual nature of HD 54786 as both an X-ray binary and an evolved star, and explores its potential evolutionary path within HMXBs.

Findings

HD 54786 may belong to both BeXRBs and SgXBs populations

MAXI J0709-159 shows low-level activity and limited circumstellar material

HD 54786 exhibits dual optical characteristics and an evolved phase

Abstract

In our previous study (Bhattacharyya et al., 2022), HD~54786, the optical counterpart of the MAXI J0709-159 system, was identified to be an evolved star, departing from the main sequence, based on comparisons with non-X-ray binary systems. In this paper, using color-magnitude diagram (CMD) analysis for High-Mass X-ray Binaries (HMXBs) and statistical t-tests, we found evidence supporting HD 54786's potential membership in both Be/X-ray binaries (BeXRBs) and supergaint X-ray binaries (SgXBs) populations of HMXBs. Hence, our study points towards dual optical characteristics of HD~54786, as an X-ray binary star and also belonging to a distinct evolutionary phase from BeXRB towards SgXB. Our further analysis suggests that MAXI J0709-159, associated with HD 54786, exhibits low-level activity during the current epoch and possesses a limited amount of circumstellar material. Although similarities with the previously studied BeXRB system LSI +61$^{\circ}$ 235 (Coe et al., 1994) are noted, continued monitoring and data collection are essential to fully comprehend the complexities of MAXI J0709-159 and its evolutionary trajectory within the realm of HMXBs.