An international team of astronomers led by Dr. Iris de Ruiter shows that the stars of white and red dwarf orbiting each other every two hours emit radio bursts.
Follow-up observations using optical and x-ray telescopes allowed researchers to reliably determine the origin of radio bursts.
The findings explain the causes of such radio emissions seen throughout the Milky Way galaxy for the first time.
What triggers a radio burst?
In recent years, better analytical techniques have given researchers the ability to detect radio pulses that appear to come from stars in the Milky Way, lasting seconds to minutes.
There have been many hypotheses about what triggers these pulses, but up until now there has been no difficult evidence of those sources.
The study led by Dr. De Luiter while at the University of Amsterdam changed this.
In her final year of her PhD, she developed a method to search for radio bursts from seconds to minutes in the historic archives of Lofar, a Dutch low-frequency array telescope.
While improving this method, Dr. De Ruiter discovered a single pulse in a 2015 observation. She then discovered six more pulses when she sifted through more archive data from the same empty patch. All of these came from a source called ILTJ1101.
Discover red and white stars
Tracking observations of Arizona’s 6.5m multiple mirror telescopes and Texas (USA) hobby and Everly telescope showed that it is not a single flashing star, but two stars that together cause radio pulses.
The two stars, the red dwarf and the white dwarf, orbit a common center of gravity every 125 minutes. They are located about 1600 light years from us in the direction of a large dipper, also known as the Plough, among the URSA main constellations.
Astronomers believe that radio emissions are caused by interactions between the red d star and the white d star magnetic field.
Astronomers will be studying the ultraviolet emissions of these intertwined stars in detail. This helps you determine the temperature of white dwarfs and learn more about the history of white and red dwarfs.
Dr. De Ruiter said: “It was especially cool to add new pieces to the puzzle, and we worked with experts in all kinds of astronomy fields.
“The various techniques and observations have brought us a little closer to the solution in a bit more step-by-step fashion.”
Breaking the monopoly of neutron stars
For this discovery, astronomers now know that neutron stars do not have a monopoly on bright radio bursts.
In recent years, other research groups have discovered around ten studies on such radio emission systems. However, these groups were unable to prove whether these pulses came from white dwarfs or neutron stars.
Researchers are currently searching LOFAR data to find more of these long-term pulses.
“Perhaps these types of radio pulses have many hidden radio pulses, and each discovery teaches us something new,” said Dr. Kaustub Rajwade, a co-author from Oxford University.
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