Models of stellar evolution have difficulty producing black holes in close binaries with masses ten times that of the sun, which is consistent with the fact that the most massive stellar black holes known so far all have masses within one standard deviation of that. This paper report a mass of 15.65 ±1.45 times that of the sun for the black hole in the recently discovered system M 33 X-7, which is located in the nearby galaxy Messier 33.
- Jerome A. Orosz
- Jeffrey E. McClintock
- Tsevi Mazeh
