Simulations reveal what actually occurs when a black hole consumes a neutron star
Caltech's supercomputer simulations depict black holes devouring neutron stars with extreme detail.
The study, led by astrophysicist Elias Most at Caltech, utilized state-of-the-art simulations to explore what happens when a black hole consumes a neutron star. The research, published in The Astrophysical Journal Letters, used advanced supercomputers to uncover the sequences leading to such cosmic events. One of the key findings is how the neutron star is affected moments before it gets absorbed by the black hole. The simulations reveal that quakes, similar to those on Earth during an earthquake, occur on the star's surface as it's subjected to intense gravitational forces from the black hole.
The detailed simulations, run on the Perlmutter supercomputer at Lawrence Berkeley National Laboratory, highlighted how the crust of a neutron star cracks under the immense gravitational pull of a black hole. Elias Most describes these crack formations as akin to the opening of rifts, which eventually triggers magnetic ripples known as Alfvén waves. These waves spread across the star, potentially generating fast radio bursts detectable from Earth as brief radio flashes lasting only milliseconds.
Image: Yoonsoo Kim/Caltech
Additionally, the simulations provided fresh insights into the formation of shock waves and their potential to release various forms of energy, including radio waves, X-rays, and gamma rays. This happens when the black hole starts consuming the neutron star, creating a burst of energy before the black hole stabilizes itself in silence. These shock waves are among the most energetic dynamic phenomena, theorized in the universe, offering crucial insights into the nature of such extreme cosmic events.
A series of three simulated images showing a black hole merge with (and consume) a neutron star. Image: Elias Most/Caltech
Moreover, the simulations proposed a theory for a black hole pulsar, a rare and exotic object where a black hole mimics the characteristics of a pulsar—a rapidly spinning star emitting cosmic beams. This theoretical framework had been hypothesized but now, with the simulation providing a detailed model, scientists have practical insights into how such an object forms and behaves. Surrounding magnetic winds from the remnants of the star recreate the pulsar's characteristic lighthouse-like beams, contributing another layer of understanding to this cosmic interplay.
Yellow lines indicate magnetized outflows whipping around a black hole in this simulation image. Image: Yoonsoo Kim/Caltech
The comprehensive nature of these simulations was compared with real-world observations, notably those from the LIGO-Virgo-KAGRA Collaboration, known for their pioneering work in detecting gravitational waves. These combined data streams enhance the insights into neutron star-black hole collisions. Elias Most underscores the complexity of simulating these events, as they require not just the equations from general relativity but also involve nuclear physics and plasma dynamics. This research is crucial in progressing our understanding of interactions at the highest energy scales in the universe.
Sources: Gizmodo, Caltech