Seems the PR people got the most important figure wrong, the measured mass is 2.14 +0.1 -0.09 M_sun, as per the preprint (and nature abstract[1]): https://arxiv

Seems the PR people got the most important figure wrong, the measured mass is 2.14 +0.1 -0.09 M_sun, as per the preprint (and nature abstract[1]): https://arxiv.org/abs/1904.06759 https://arxiv.org/abs/1904.06759 The 2.17 M_sun figure is instead the hypothesised upper limit on the neutron star mass, derived from the equations of state that survive recent LIGO observations. [1]: https://www.nature.com/articles/s41550-019-0880-2 https://www.nature.com/articles/s41550-019-0880-2