Constraining the Overcontact Phase in Massive Binary Evolution I. Mixing in V382 Cyg, VFTS 352, and OGLE SMC-SC10 108086

Understand

As potential progenitors of several exotic phenomena including gravitational wave sources, magnetic stars, and Be stars, close massive binary systems probe a crucial area of the parameter space in massive star evolution.

• Despite the importance of these systems, large uncertainties regarding the nature and efficiency of the internal mixing mechanisms still exist.
• In this work, we aim to provide robust observational constraints on the internal mixing processes by spectroscopically analyzing a sample of three massive overcontact binaries at different metallicities.
• Using optical phase-resolved spectroscopic data, we perform an atmosphere analysis using more traditional 1D techniques and using state-of-the-art 3D techniques.