Extended Data Fig. 3: Bound from birth fraction versus mass for surviving and non-surviving binaries.

The fraction is shown with open, blue circles (filled, orange triangles) for surviving (non-surviving) binaries. The mass is the maximum of the two stars’ final masses. The error bars show the standard deviation, from the Bayesian formula \(\sqrt{\frac{(N-k+1)(k+1)}{(N+3){(N+2)}^{2}}}\), where k is the number of bound binaries and N is the total number of binaries in the mass bin. From left to right k is 194, 306, 157, 16, 1 for the survivors and 117, 259, 182, 86, 6 for the non-survivors. From left to right N is 224, 397, 251, 75, 10 for the survivors and 150, 331, 282, 145, 18 for the non-survivors. While high mass stars tend to form in multiple systems, many of these are disrupted by exchanges, leading to a decline in the overall bound-from-birth fraction with mass.