Black holes can rekindle dead stars, even if only for a few seconds, according to a new study.
Stars that sway too close to the threatening gaps can cause tidal disturbances (TDEs). Stars are pulled by their strong gravitational field in the direction of the black hole and finally torn apart by the extreme tidal forces.
A group of physicists studied and modeled the interaction with computer simulations based on equations of general relativity. They found that during the violent process, luminous stars are destroyed while dark white dwarfs left over from the core of dead stars are revived. The strong tidal forces can compress the white dwarfs and trigger thermonuclear reactions for a few seconds.
Images from computer simulations of a white dwarf to be burst by a local black hole of 1000 solar masses. Picture credits: Anninos et al.
It's a "likely outcome" if the White Dwarf is massive enough and tidal compression is strong enough, the study said on arXiv. The compressive strength depends on the mass of the black hole, it should be in the middle mass range of about 100 to 100,000 solar masses.
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If a black hole is too small, its gravitational effects are minimal. However, if it is too large, the white dwarf will be swallowed up by the black hole before its tidal forces can take over. However, compression forces are not enough to initiate the thermonuclear fusion process, and the white dwarf remains dead.
"It is important to know how many black holes exist in the intermediate mass to answer the question where supermassive black holes are coming from, "said Chris Fragile, co-author of the study and professor of physics and astronomy at the College of Charleston, South Carolina. "The discovery of black intermediate holes by tidal disturbance events would be a tremendous advance."
The work was accepted and is expected to appear in the Astrophysical Journal. ®