‘Zombie’ Stars: Rare Type Of Black Holes Can Bring Dead Stars Back To Life

White dwarf stars are briefly brought back to life when they pass near a intermediate black hole, reveals a new study.

White dwarf star,
Jurik Peter / Shutterstock

White dwarf stars are briefly brought back to life when they pass near a intermediate black hole, reveals a new study.

An exciting new study on black hole properties has uncovered that intermediate black holes have the power to reanimate dead stars, albeit temporarily, announced a news release from the College of Charleston in South Carolina.

As the Inquisitr previously reported, intermediate black holes hold between 1,000 and 10,000 times the mass of our sun and are notoriously difficult to study. In fact, astronomers had no solid proof this rare class of black holes even existed until our X-ray telescopes spotted one such object munching on a star in 2003.

According to the new research, available on the pre-print server arXiv, intermediate black holes have a curious effect on white dwarf stars — or the dense core left behind after big stars run out of hydrogen and collapse into a burned-out stellar corpse, notes Space.

When a white dwarf happens to pass in front of an intermediate black hole, the two objects interact dramatically via the incredible gravitational pull of the black hole. This violent process, known as a tidal disruption event, stretches and distorts the stellar remnant until it once again sparks nuclear fusion reactions.

This causes the dead star to awaken and spring back to life, going from white dwarf to “cosmic zombie” for a very brief moment, explains the media outlet.

Once reignited, the stellar corpse goes through a supernova-like explosion and starts churning helium, carbon, and oxygen into heavier elements, regenerating calcium and iron.

This sudden resurrection only lasts for a few seconds, but might be enough to explain why astronomers sometimes detect larger amounts of calcium and less iron than expected in some supernovae, notes Gizmodo.

“This is a potential explanation for an unusual type of ‘transient’ or temporary source — one that appears and then disappears — which contains substantial amounts of calcium, but not so much iron or nickel, as we might expect in a ‘typical’ white dwarf generated supernova (Type Ia supernovae),” said Prof. K.E. Saavik Ford, a researcher at CUNY Borough of Manhattan Community College and the American Museum of Natural History.

Ford was not part of the new study, which was led by Peter Anninos of the Lawrence Livermore National Laboratory in California and co-authored by the College of Charleston’s Chris Fragile, among other researchers from various U.S. universities.

Aside from bringing white dwarfs back from the dead, the tidal disruptions caused by intermediate black holes can also produce gravitational waves — an astronomical event observed for the first time in 2017 with the help of the Laser Interferometer Gravitational-Wave Observatory (LIGO) in ‎Livingston, Louisiana, the Inquisitr recently reported.

“Tidal disruptions of white dwarf stars by intermediate-mass black holes are complex and violent cosmic events capable of generating significant electromagnetic and potentially observable gravitational wave energies,” the authors wrote in their paper, which has been accepted for publication in The Astrophysical Journal.

These conclusions are based on computer simulations aimed at finding out what happens when a white dwarf meets a medium-size black hole. While no direct observations of this type of gravitational waves have ever been made, the team is confident that the European Space Agency’s Laser Interferometer Space Antenna (LISA) will be able to spot them — that is, once it becomes operational in 2034, as reported by the Inquisitr.

“Although these signals fall within LISA’s frequency band, the amplitudes are sufficiently small that they will not likely be observed except at source distances within [around 33,000 to 333,000 light-years], which, if current estimates of the [white dwarf to intermediate-mass black hole] disruption rate… are correct, would be extremely rare events,” Anninos’ team detailed in the study.