White dwarf “flashes” every 2h (and has red companion)

An international team of astronomers led by dwarf scientists has shown that a white dwarf and a red dwarf, which orbit each other every two hours, emit radio pulses.

Thanks to observations made with various telescopes, the investigators were able to determine the origin of these signs for the first time. His results were in the journal Nature Astronomy.

In recent years, thanks to better analysis techniques, researchers have detected radio pulses that last between seconds and minutes and that seem to originate from Milky Way stars. There are many hypotheses about what it triggers these wrists, but so far there have been no concrete evidence. An international study led by Ruiter’s Iris from the Netherlands has changed this situation.

De Ruiter, who received his doctorate from the University of Amsterdam in October 2024, is now a postdoctoral researcher at the University of Sydney (Australia). During the last year of his doctorate, he developed a method to look for Radio from seconds to minutes in the Lofar file. While improving the method, it discovered a only pulse In the 2015 observations. When he later analyzed more archive data from the same area of ​​the sky, he discovered six more pulses. All pulses come from a source called ILTJ1101.

Red Dwarf and White Dwarf

Subsequent observations with 6.5 m (Multiple Mirror Mirror Mirror) in the US state of Arizona, and the Hobby-Eberly telescope in Texas showed that It is not a star that blinks, but two stars which together are the cause of the pulse. The two stars, one red dwarf and a white dwarforbit a center of gravity common to each 125 minutes. They are located about 1600 light years away from the Ursa Maior constellation.

Astronomers think that radio emission is caused by the interaction of the red dwarf with the magnetic field of the white dwarf.

In the future, astronomers plan to study in detail the ultraviolet emission of ILTJ1101. This will help determine the temperature of the white dwarf and learn more about the history of white and red dwarfs.

“It was especially interesting to add new pieces to Puzzle,” Ruiter’s Iris. “We worked with experts of all kinds of astronomical disciplines. With different techniques and observations, we approached a little more of the solution, step by step. ”

Unfeeling monopoly

Thanks to this discovery, astronomers now know that neutron stars do not have the monopoly of bright radio pulses. In recent years, about ten radio systems of this type have been discovered by other research groups. However, these groups have not yet been able to prove whether these pulses come from a white dwarf or a neutron star.

Researchers are now researching all Lofar data to find more long -term pulses. Coauthor Kaustubh Rajwade (University of Oxford, UK), added: “There are probably many more of these types of radio pulses hidden in the Lofar file and each discovery teaches us something new.”