2023-07-24 06:00:05
Astronomers have identified a type of stellar object that, in some inexplicable way, appears to defy death.
Illustration of a magnetar propelling jets of energy into space, 15,000 light years away.
Image Credit: ICRAR
Located regarding 15,000 light-years from Earth, this object appears to be a magnetar – the collapsed core of an ancient giant star. Its mass is equivalent to that of the Sun (The Sun (Sol in Latin, Helios or Ήλιος in Greek) is the star…), concentrated in a sphere (In mathematics, and more precisely in Euclidean geometry, a…) no larger than a city. The strength of its magnetic field (In physics, the magnetic field (or magnetic induction, or flux density…) is more than a quadrillion times that of the Earth. Magnetars, these small rotating spheres, can emit ultra-bright jets of electromagnetic radiation, including radio waves that pulse at regular rates. threshold beyond which the star’s magnetic field becomes too weak to generate high-energy radiation (In common sense, energy designates everything that allows work to be done, manufacture of energy, etc.).
Surprisingly, the newly discovered magnetar still seems to be emitting bright, constant radiation, well beyond the death line.
“According to our observations, the object is rotating too slowly to produce radio waves – it is below the death line,” said Natasha Hurley-Walker, a radio astronomer at ICRAR (International Center for Radio Astronomy Research) in Australia. “Assuming it’s a magnetar, it shouldn’t be possible for this object to produce radio waves. Yet we detect them.”
If confirmed, this long-period magnetar might represent a new class of stellar objects that defies all current theoretical models.
Beyond the “death line”
The magnetar was discovered by the Murchison Widefield Array radio telescope in Australia. Half a dozen other facilities around the world have confirmed the discovery and studied the object.
Image Credit: ICRAR
Scientists discovered this persistent magnetar, named GPM J1839-10, in September 2022. A search of astronomical records subsequently revealed previous detections of the object dating back to 1988. Observations showed that the object pulsed bright, powerful radio waves every 22 minutes (Primary form of a document: Right: One minute is the original of an act. …), shining intensely for regarding five minutes before s darken once more. This is an unprecedented observation; most magnetars emit radio waves with a cycle of seconds to minutes. This ultra-long period suggests that the magnetar is spinning very slowly past the death line.
These peculiar characteristics – the object’s slow rotation, its long pulsation period and the extreme longevity of its radio emission – contradict all models, the researchers wrote.
“This remarkable object challenges our understanding of neutron stars and magnetars, which are among the most exotic and extreme objects in the universe,” Hurley-Walker said. “Whatever the mechanism behind it, it’s extraordinary.”
The team’s research was published July 19 in the journal Nature.
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