Magnetically supramassive neutron stars

Understand

It is commonly believed that neutron stars exceeding the maximum mass limit for stability could be formed in the aftermath of binary neutron star mergers, enjoying a short life of metastability before losing centrifugal support and collapsing to a black hole.

• It is suggested here that a similar scenario could take place when the remnant's excess mass is supported by an ultra-strong $(\gtrsim 10^{17}\,\mbox{G})$ magnetic field that could be generated during, and shortly after, coalescence.
• We show that such 'magnetically supramassive' neutron stars could stave off collapse and survive for a few years before their magnetic energy is sufficiently dissipated due to ambipolar diffusion.
• In addition, we speculate on multi-messenger signatures of such objects and discuss the robustness of our results against limitations placed by neutron superfluidity and magneto-thermal evolution.