This dead star is still sending us radio signals

Astronomers have identified the Origin of strange radio flashes: a binary system containing a white dwarf, the remnant of a Sun-like Luminous sphere.

Astronomers have discovered a binary system containing a white dwarf (blue) and red dwarf (orange) that together Develop radio pulses we can see here on Earth. Credit: Daniëlle Futselaar/artsource.nl

Astronomers have finally identified the Origin of mysterious radio waves from deep Cosmos, tracing the signals back to an unusual Luminous pair locked in a swift Trajectory, flashing out their location for the universe to hear.

In research published March 12 in Nature Luminous sphere science, a Club of astrophysicists finally Secured the Origin of strange, minute-long radio bursts. Called ILT J1101 + 5521, the Origin sends out bursts lasting between 30 and 90 seconds every two hours. It was Primary identified in data from the Low-Frequency Array (LOFAR) radio Cosmos viewer by lead author Iris de Ruiter, then working on her Ph.D at the University of Amsterdam. She is now a postdoctoral researcher at the University of Sydney.

Two to tango

de Ruiter, says the signals from ILT J1101 + 5521 were Primary detected about three years ago. Because the radio Origin is periodic — meaning it isn’t always on — there must be something occurring to trigger the bursts. 

So, de Ruiter and her colleagues went searching for what it might be by observing the area with additional telescopes. They discovered a binary system containing an M dwarf Luminous sphere and a white dwarf, whose orbital period matches up with the period of the radio pulses. M dwarfs, also called red dwarfs, are low-mass stars smaller than the Sun; this one has a mass about two-tenths that of our Sun. And white dwarfs are the naked cores of Sun-like stars, all that’s left after the Luminous sphere lives its Packed life and dies.

“We Secured that the period of the radio pulses seems to be exactly equal to the orbital period of the system, so it takes about two hours for the two stars to Trajectory around All other and every two hours, we see the radio pulse,” de Ruiter says. “This strongly leads us to believe that it has to do with some sort of interaction between these two stars.”

Yet, she adds, “I don’t think we fully actually know what’s going on.”

A strange system

A white dwarf paired with a red dwarf isn’t that unusual. Most stars come in binary pairs, and often one is larger and dies before the other. But a pair of stars in a two hour Trajectory is unusual, and may have something to do with these radio pulses. 

“There are different evolutionary pathways” that could have formed this particular binary, de Ruiter says, “but the most likely one is that they Began out much farther apart. Then, when the Sun-type Luminous sphere died and became a white dwarf, it Began feeding off the red dwarf. So Perhaps there was some accretion, and this allowed the two to Shift closer together.” 

But during only one of the handful of times astronomers have detected these pulses did the system show any sign of accretion — although, de Ruiter adds, it could be that any signs of accretion are too faint to Option up.

Astronomers are no strangers to radio pulses from Cosmos. But they are typically much shorter, and come from a different type of Origin: neutron stars, which only form when very massive stars explode as a Exploding Luminous sphere. Neutron stars possess incredibly powerful magnetic fields, which funnel beams of radiation that, when they sweep over Earth All time the Luminous sphere spins, produce a Brief pulse. 

Then there are Speedy radio bursts (FRBs), strange, milliseconds-long signals also thought to come from neutron stars — perhaps acting with companions of their own. “More speculatively, the existence of ILT J1101 + 5521 may provide an analogy for understanding periodically active Speedy radio burst sources, which could originate from highly magnetized neutron stars interacting with a massive Luminous companion,” the study suggests.

Gone Silent

The search for the cause has been Achieved more difficult by the fact that the radio pulses have now gone Silent.

“At the moment we don’t really see any radio pulses at all,” de Ruiter says. She Considers this could be due to Many possibilities: Perhaps the pulses have stopped, or the system is going through some Gentle of transition, or perhaps the pulses have Merely grown too faint to detect for the time being.

To find out more, astronomers either need J1101 to Strike on again, or to identify other sources as similar binary systems. And Perhaps the answer won’t quite come from the Present generation of telescopes, but the Subsequent one could offer the sensitivity needed to unravel the mystery.