Along the coast, waves break with a familiar sound. The gentle swash of the surf on the seashore can lull us to sleep, while the pounding of storm surge warns us to seek shelter.

Yet these are but a sample of the sounds that come from the coast. Most of the acoustic energy from the surf is far too low in frequency for us to hear, traveling through the air as infrasound and through the ground as seismic waves. 

An international team led by Dr. Hila Glanz of the Technion – Israel Institute of Technology has uncovered a new origin for hypervelocity white dwarfs — stellar remnants racing through space at more than 2000 km/s.

Using advanced 3D hydrodynamic simulations, the researchers showed that when two rare hybrid white dwarfs merge, the heavier star can undergo a double-detonation explosion. This blast ejects the surviving remnant of its companion at hypervelocity, fast enough to escape the Milky Way.

The findings, published in Nature Astronomy, explain both the extreme speeds and unusual properties of known hypervelocity white dwarfs, while also pointing to a new pathway for faint and peculiar Type Ia supernovae.

The study was conducted by researchers from the Technion, Universität Potsdam, and the Max Planck Institute for Astrophysics, and has implications for future transient surveys and Gaia discoveries.