Astronomers have discovered that a pair of stars—one white dwarf and one red dwarf—are sending out radio pulses every two hours.
This is the first time scientists have confirmed the source of such signals, thanks to observations using multiple telescopes.
Their findings were recently published in Nature Astronomy.
For years, scientists have detected strange radio pulses lasting from seconds to minutes, coming from stars in the Milky Way.
There were many theories about what could be causing them, but until now, no one had solid proof. This breakthrough comes from an international team led by Iris de Ruiter from the Netherlands.
During her Ph.D. at the University of Amsterdam, de Ruiter developed a method to search for these signals in the LOFAR telescope archive.
While refining her method, she found a single pulse in 2015 data. Digging deeper into past observations, she discovered six more pulses, all coming from the same source: ILTJ1101.
Further research using telescopes in the U.S. confirmed that ILTJ1101 is not just one flashing star but a pair of stars orbiting each other every 125 minutes. This system is located about 1,600 light-years away in the direction of the Big Dipper constellation.
The two stars involved are a white dwarf, which is the leftover core of a dead star, and a red dwarf, a small, cooler star. Astronomers believe the radio pulses are caused by the red dwarf interacting with the strong magnetic field of the white dwarf.
Scientists now plan to study the ultraviolet light coming from ILTJ1101 to learn more about the white dwarf’s temperature and the history of these types of star systems.
“It was exciting to piece together this puzzle,” de Ruiter said. “By combining different techniques and working with experts from different areas, we got closer to understanding what’s happening.”
Breaking the Monopoly on Radio Pulses
Until now, scientists thought only neutron stars—some of the densest objects in the universe—could produce these powerful radio bursts. This discovery proves that white dwarfs can do it too.
In recent years, about ten other systems have been found emitting similar radio pulses, but none had been confirmed to come from a white dwarf. Now, astronomers are searching the LOFAR data for more of these mysterious signals.
“There are probably many more of these signals hiding in the data,” said co-author Kaustubh Rajwade from the University of Oxford. “Every new discovery helps us learn more about the universe.”
