A ring of planetary debris, filled with evenly spaced Moon-sized structures, has been found orbiting a white dwarf star at close range. The discovery was made by an international team of researchers led by University College London and suggests the existence of a nearby planet, located in the habitable zone of its star, a region where average temperatures allow the existence of liquid water.
White dwarfs are what’s left after Sun-like stars run out of hydrogen reserves, and not much is known about the planetary systems that may exist around them.
In this study, the authors collected measurements of the light from the white dwarf WD1054226 and found significant decreases in its luminosity, caused by something surprising: There were 65 clouds of evenly spaced planetary debris orbiting the star every 25 hours.
Want to stay on top of the best tech news of the day? Access and subscribe to our new youtube channel, Kenyannews News. Every day a summary of the main news from the tech world for you!
They concluded that the transiting structures, which dim the star every 23 minutes, can be held in such a precise arrangement by the gravitational influence of a nearby planet. “This is the first time that astronomers have found a type of planetary body in the habitable zone of a white dwarf,” said Jay Farihi, author who led the study.
According to him, the structures observed are irregular and dusty, with an aspect that refers more to a comet than to a spherical and solid body. “Their absolute regularity, passing in front of the star every 23 minutes, is a mystery that we currently cannot explain,” he said.
However, Farihi is cautious, noting that more evidence is needed to confirm the presence of a planet there. “We have not been able to observe the planet directly, so confirmation may come by comparing computer models with new observations of the star and the debris orbiting it,” suggested the author.
The importance of discovery
He believes that perhaps the bodies are held in an evenly spaced orbital pattern due to the gravitational influence of some nearby planet.
“Without that influence, friction and collisions would cause the structures to disperse, losing the precise regularity that we observe,” he said. “A precedent for this ‘grazing’ is how the gravitational pull of the moons of Neptune and Saturn helps create ring structures orbiting these planets.”
In addition, the discovery of the habitable zone was a pleasant surprise for the team. “We believe that this orbit around the white dwarf was cleared during the star’s giant phase, and that any planet that could, perhaps, harbor water and life would be recent,” Farihi noted. “This area would be habitable for at least two billion years, including at least a billion years in the future.”
The habitable zone is the area where temperature theoretically allows liquid water to occur on the surface of a planet. In the case of white dwarfs, the habitable zone is smaller and closer to them, because they emit less heat compared to stars like the Sun. The structures observed in the study orbit an area that would be swallowed by the star in the red giant phase, so they must have graduated or arrived there recently.
As more than 95% of known stars will eventually become white dwarfs (the exceptions are the most massive stars that, after exploding, can become black holes or neutron stars), the study may tell you a little about what to expect in the future. from our neighborhood. “As the Sun will become a white dwarf in a few billion years, our study offers a peek into the future of the Solar System,” said Farihi.
The article with the results of the study was published in the journal Monthly Notices of the Royal Astronomical Society.
