A slow cosmic blinking ball puzzles astronomers

Astronomers have discovered the slowest pulsar ever. Pulsars are a cosmic stroboscope. Typically, a short pulse of radio waves appears dozens or hundreds of times per second. The new organism has only been doing this about three times an hour, but for at least 33 years. And no one understands how this is possible. This discovery may shed new light on the death of stars, since it almost certainly concerns the “dead remnants” of a star.

Natasha Hurley-Walker of Australia’s Curtin University and colleagues discovered the slow, blinking orb with the Murchison Widefield Array, a radio telescope in Western Australia. Then they found occasional beeps in old observations from other radio observatories, dating back to the late 1980s. The discovery was published this week in a scientific journal nature.

According to the authors, it is almost certainly not a “normal” pulsar. Pulsars are the so-called neutron stars – the remnants of exploding giant stars. They are very compact: heavier than the Sun, but only 25 kilometers in diameter. Some spin faster than a hand blender, and they have a strong magnetic field. Thanks to all of these extreme properties, a pulsar produces rotating beams of particles and radiation, like a runaway beacon. When such a beam sweeps across the Earth, a short pulse of radio radiation can be seen.

But if the pulsar rotates too slowly (or if its magnetic field isn’t strong enough), this mechanism no longer works. GPM J1839-10, as the new object is dubbed, only produces one pulse every 22 minutes, so it can’t be an ordinary pulsar. Some other neutron stars, with a stronger magnetic field (they are called magnetars), sometimes exhibit somewhat slower pulsations, but this almost always occurs in the aftermath of a surface explosion, and lasts at most a few weeks or months.

White dwarf statement

Furthermore, a very slow, blinking magnetore would also be expected to emit X-rays, which is not the case with GPM J1839-10, says co-author Nanda Ria of the Institute of Space Sciences in Barcelona. Instead, astronomers think it may be a white dwarf, the remnant of a star like our Sun. It’s still strange, Rhea says, that no other white dwarfs have been found that produce such pulsed radio emissions.

Victoria Caspi, a pulsar expert from Canada’s McGill University, who was not involved in the research herself, spoke of a surprising discovery. Take into account that there are a lot of these slow, flickering orbs floating around in the Milky Way – they are not easy to find. However, she doesn’t want to completely omit the pulsar interpretation just yet. “Natures are often more creative than theoretical astrophysicists,” she says. “On the other hand, the white dwarf interpretation also appeals to me, especially because this idea can be tested.”

That might work with the James Webb Space Telescope. Because despite its distance of just under 20,000 light-years, you should be able to see a white dwarf with this space telescope. “This is our next challenge,” says Ria.