Solving the mystery of extreme light variability in the massive eccentric system MACHO 80.7443.1718

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Auteurs principaux: Kołaczek-Szymański, Piotr A., Łojko, Piotr, Pigulski, Andrzej, Różański, Tomasz, Moździerski, Dawid
Format: Preprint
Publié: 2024
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author Kołaczek-Szymański, Piotr A.
Łojko, Piotr
Pigulski, Andrzej
Różański, Tomasz
Moździerski, Dawid
author_facet Kołaczek-Szymański, Piotr A.
Łojko, Piotr
Pigulski, Andrzej
Różański, Tomasz
Moździerski, Dawid
contents The evolution of massive stars is heavily influenced by their binarity, and the massive eccentric binary system MACHO 80.7443.1718 (ExtEV) serves as a prime example. This study explores whether the light variability of ExtEV, observed near the periastron during its 32.8-day orbit, can be explained by a wind-wind collision (WWC) model and reviews other potential explanations. Using broadband photometry, TESS data, ground-based $UBV$ time-series photometry, and high-resolution spectroscopy, we analysed the system's parameters. We ruled out the presence of a Keplerian disk and periodic Roche-lobe overflow. Our analysis suggests the primary component has a radius of about $30\,{\rm R}_\odot$, luminosity of $\sim6.6\times10^5\,{\rm L}_\odot$, and mass between $25$ and $45\,{\rm M}_\odot$, with a high wind mass-loss rate of $4.5\times10^{-5}\,{\rm M}_\odot\,{\rm yr}^{-1}$, likely enhanced by tidal interactions, rotation, and tidally excited oscillations. We successfully modelled ExtEV's light curve, identifying atmospheric eclipse and light scattering in the WWC cone as key contributors. The system's mass-loss rate exceeds theoretical predictions, indicating that ExtEV is in a rare evolutionary phase, offering insights into enhanced mass loss in massive binary systems.
format Preprint
id arxiv_https___arxiv_org_abs_2411_05469
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Solving the mystery of extreme light variability in the massive eccentric system MACHO 80.7443.1718
Kołaczek-Szymański, Piotr A.
Łojko, Piotr
Pigulski, Andrzej
Różański, Tomasz
Moździerski, Dawid
Solar and Stellar Astrophysics
High Energy Astrophysical Phenomena
The evolution of massive stars is heavily influenced by their binarity, and the massive eccentric binary system MACHO 80.7443.1718 (ExtEV) serves as a prime example. This study explores whether the light variability of ExtEV, observed near the periastron during its 32.8-day orbit, can be explained by a wind-wind collision (WWC) model and reviews other potential explanations. Using broadband photometry, TESS data, ground-based $UBV$ time-series photometry, and high-resolution spectroscopy, we analysed the system's parameters. We ruled out the presence of a Keplerian disk and periodic Roche-lobe overflow. Our analysis suggests the primary component has a radius of about $30\,{\rm R}_\odot$, luminosity of $\sim6.6\times10^5\,{\rm L}_\odot$, and mass between $25$ and $45\,{\rm M}_\odot$, with a high wind mass-loss rate of $4.5\times10^{-5}\,{\rm M}_\odot\,{\rm yr}^{-1}$, likely enhanced by tidal interactions, rotation, and tidally excited oscillations. We successfully modelled ExtEV's light curve, identifying atmospheric eclipse and light scattering in the WWC cone as key contributors. The system's mass-loss rate exceeds theoretical predictions, indicating that ExtEV is in a rare evolutionary phase, offering insights into enhanced mass loss in massive binary systems.
title Solving the mystery of extreme light variability in the massive eccentric system MACHO 80.7443.1718
topic Solar and Stellar Astrophysics
High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2411.05469