LMC X-3 formation history

We estimated the properties of the system at four evolutionary stages: 1) at the zero-age main-sequence (ZAMS), 2) immediately before the supernova (SN) explosion of the primary, 3) immediately after the SN, and 4) at the moment when Roche-lobe overflow began. We used a hybrid approach that combined detailed calculations of the stellar structure and binary evolution with approximate population synthesis models.

This allowed us to estimate potential natal and the evolution of the BH spin. We incorporated as model constraints the most up-to-date observational information throughout, which include the binary orbital properties, the companion star mass, effective temperature, surface gravity and radius, and the BH mass and spin. We find at 5% and 95% confidence, respectively, that LMC X-3 began as a ZAMS system with the mass of the primary star in the range M_1,ZAMS_=22-31M_{sun}_ and a secondary star of M_2,ZAMS_=5.0-8.3M_{sun}_, in a wide (P_ZAMS_>~2.000days) and eccentric (e_ZAMS_>~0.18) orbit.