The Origin of the Possible Massive Black Hole in the Progenitor System of iPTF13bvn

This letter complements a formation scenario of the progenitor of the supernova iPTF13bvn proposed in Hirai (2017). Although the scenario was successful in reproducing various observational features of the explosion and pre-explosion photometry by assuming that the progenitor had a relatively large black hole companion, it lacked an explanation for the origin of the black hole itself. We now explore the possible evolutionary paths towards this binary with a relatively large black hole companion. We found that the black hole was probably produced by a very massive star that experienced common envelope evolution. According to our MESA stellar models, the primary mass should have been 70M to reproduce the required remnant mass and final separation. This indicates that iPTF13bvn was likely a rare case and normal type Ib supernovae originate from different paths.