Evrim Yazgin
Cosmos science journalist
A transient object has been detected by Australian radio astronomers which has the longest rotation of any such object yet discovered.
It may help astronomers work out what makes these enigmatic long-period radio transient objects.
Long-period radio transient objects are relatively new to science, having been first observed in about the past 10 years. They release bursts of radio waves – with a periodicity, or interval recurrence – of 10 to100 seconds. These are observed on Earth as bursts as the object rotates. Most bursts arrive with gaps of about 18 up to 54 minutes.
Last year, a team of astronomers revealed the longest known period for a radio transient which shot bursts of radio rays every 2.9 hours. That object, called GLEAM-X J0704−37, was discovered using the Murchison Widefield Array in Western Australia.
Now, a team using the CSIRO’s Australian Square Kilometre Array Pathfinder (ASKAP) radio telescope, also in Western Australia, has found an object with more than double the periodicity.
Many involved in the GLEAM-X J0704−37 study were also part of the team that found the new object.
The new radio transient, called ASKAP J183950.5−075635.0 (ASKAP J1839−0756 for short), is described in a paper published in Nature Astronomy.
It has a period, meaning the object creating the radio bursts is spinning, every 6.45 hours.
The long-period radio transients are sometimes referred to as “cosmic lighthouses”.
It is not clear what they are, but the authors say that astronomers theorise they could be highly magnetised white dwarfs or neutron stars.
“ASKAP J1839−0756 shares several properties with other known long-period radio transients, which suggests a common origin and emission mechanism across this class of objects,” the authors write.
“The discovery of ASKAP J1839−0756 can improve our understanding of the population density of long-period radio transients in future studies, and the presence and properties of interpulse emission can test theoretical models of compact objects.”
