Mysterious Object in Space Pulsed on a 62-Minute Beat, Then Stopped

He spent years searching for another and found little, and eventually turned to other work. Two decades later, while looking for something else, the pattern appeared again.

How the new source was confirmed

By 2022 Hyman was hunting for millisecond pulsars, which are rapidly spinning neutron stars. One candidate in archival observations from the MeerKAT telescope behaved oddly.

"One object that we detected in archival observations of the MeerKAT telescope had pulsar-like properties, but the 'pulses' occurred many minutes apart, and at seemingly regular intervals," Hyman said.

He then checked other archives. The ASKAP telescope had been watching the same patch of sky on exactly the same day. That 10-hour observation confirmed the 62-minute period.

Why LPTs are hard to explain

The category took shape with GLEAM-X J1627-5235, observed in 2018 and first reported in 2022. Since then, around a dozen similar pulsators have turned up in radio surveys across the Milky Way. Hyman's 2002 detection, GCRT J1745-3009, now counts among them in hindsight.

Three types of dead star are the leading suspects: pulsars, magnetars and white dwarfs. Pulsars sweep beams of radio emission across space like lighthouses, and magnetars are their more intensely magnetic relatives.

Neutron stars like these usually pulse much faster. LPTs can take hours between flashes, and at such slow rotation rates a conventional pulsar should struggle to produce radio emission at all.

White dwarfs fit better in some cases. They can rotate more slowly, and interaction with a companion star can generate powerful radio signals. Some LPTs have already been linked to white dwarf binary systems.

That does not make every LPT a white dwarf. Their varied pulse patterns, polarization and periods leave open the possibility that more than one mechanism, and more than one kind of object, is at work.

Hyman said he wants to know whether the group is one family. "Are all LPTs one type of object?" he said. "Do they represent a new subcategory of white dwarfs or neutron stars? An entirely hitherto unknown type of object?"