Toward early-type eclipsing binaries as extragalactic milestones: IV. Physical properties of three detached O/B-type systems in the LMC

TL;DR

This paper provides detailed physical parameters for three early-type eclipsing binaries in the LMC, including masses, radii, temperatures, and orbital solutions, enhancing understanding of massive star evolution in an extragalactic context.

Contribution

It offers new, precise measurements of physical properties for three early-type binary systems in the LMC, including a novel mass-luminosity relation and analysis of internal structure constants.

Findings

Masses range from 11.7 to 22.1 solar masses.

All systems are evolutionarily advanced on the main sequence.

HV 2274 shows a significant period decrease, possibly due to a companion.

Abstract

We present a complete set of physical parameters for three early-type eclipsing binary systems in the Large Magellanic Cloud (LMC): OGLE LMC-ECL-17660, OGLE LMC-ECL-18794, and HV 2274, together with the orbital solutions. The first and third systems comprise B-type stars, while the second has O-type components and exhibits a total eclipse. We performed a complex analysis that included modeling light and radial velocity curves, O-C analysis, and additional non-LTE spectroscopic analysis for the O-type system. We found that OGLE LMC-ECL-17660 is at least a triple and, tentatively, a quadruple. A significant non-linear period decrease was determined for HV 2274. Its origin is unclear, possibly due to a faint, low-mass companion on a wide orbit. The analyzed components have masses ranging from 11.7 M$_\odot$ to 22.1 M$_\odot$, radii from 7.0 R$_\odot$ to 14.2 R$_\odot$, and temperatures between 22500 K and 36000 K. For HV 2274, the precision of our masses and radii is about six times higher than in previous studies. The position of the components of all six systems analyzed in this series on the mass-luminosity and mass-radius diagrams indicates they are evolutionarily advanced on the main sequence. Our sample contributes significantly to the knowledge of physical parameters of early-type stars in the mass range of 11 M$_\odot$ to 23 M$_\odot$. A new mass-luminosity relation for O and B-type stars in the LMC is provided. Additionally, we used the measured apsidal motion of the systems to compare the observational and theoretical internal structure constant.