Magnetically driven baryon winds from binary neutron star merger remnants and the blue kilonova of August 2017

Understand

The observation of a radioactively-powered kilonova associated with the first binary neutron star (BNS) merger detected in gravitational waves proved that these events are ideal sites for the production of heavy r-process elements.

• However, the physical origin of the ejected material responsible for the early ("blue") and late ("red") components of this kilonova is still debated.
• Here, we investigate the possibility that the early/blue kilonova originated from the magnetically driven baryon wind launched after merger by the metastable neutron star remnant.
• Exploiting a magnetized BNS merger simulation with over 250 ms of post-merger evolution, we can follow for the first time the full mass ejection process up to its final decline.