An eclipsing binary distance to the Large Magellanic Cloud accurate to 2 per cent

TL;DR

This paper presents a highly precise distance measurement to the Large Magellanic Cloud using long-period, late-type eclipsing binary stars, achieving 2.2% accuracy, which supports more accurate determination of the Hubble Constant.

Contribution

It introduces a method using cool giant eclipsing binaries to measure LMC distance with improved accuracy, reducing systematic uncertainties associated with hot star systems.

Findings

LMC distance determined as 49.97 +/- 0.19 (stat) +/- 1.11 (sys) kpc

Achieved 2.2% accuracy in distance measurement

Supports a 3% or better determination of the Hubble Constant

Abstract

In the era of precision cosmology it is essential to determine the Hubble Constant with an accuracy of 3% or better. Currently, its uncertainty is dominated by the uncertainty in the distance to the Large Magellanic Cloud (LMC) which as the second nearest galaxy serves as the best anchor point of the cosmic distance scale. Observations of eclipsing binaries offer a unique opportunity to precisely and accurately measure stellar parameters and distances. The eclipsing binary method was previously applied to the LMC but the accuracy of the distance results was hampered by the need to model the bright, early-type systems used in these studies. Here, we present distance determinations to eight long-period, late- type eclipsing systems in the LMC composed of cool giant stars. For such systems we can accurately measure both the linear and angular sizes of their components and avoid the most important problems related to the hot early-type systems. Our LMC distance derived from these systems is demonstrably accurate to 2.2 % (49.97 +/- 0.19 (statistical) +/- 1.11 (systematic) kpc) providing a firm base for a 3 % determination of the Hubble Constant, with prospects for improvement to 2 % in the future.