A new study reveals astronomers have found mysterious planetary bodies orbiting around the safe zone of a dead star for the first time, potentially pointing to a new planet in the area that could support life.
Many often think of stars as fixed, virtually immortal cosmic entities, but the harsh reality is that all stars are living on a countdown clock. While the largest and rarest stars in the universe will one day explode and became black holes or neutron stars, the vast majority of them — including our own sun — will eventually burn through their vast supply of hydrogen and glow with just the embers of its former self.
This transformation turns the former star into what’s known as a white dwarf. Though experts have uncovered many mysteries surrounding these dead stars, we still know very little about the planetary systems that orbit around them.
Now, in a potential breakthrough, researchers published a study Friday in the Monthly Notices of the Royal Astronomical Society announcing that they’ve found strange debris with structures the size of moons orbiting around one of these white dwarfs in our very own galaxy.
What’s more is that they found the debris in the habitable zone of the star — sometimes referred to as the Goldilocks zone — where temperatures are not too hot or too cold to make life impossible.
“This is the first time astronomers have detected any kind of planetary body in the habitable zone of a white dwarf,” said Jay Farihi, lead author of the study and professor in the physics & astronomy department of University College London, in a press statement. “The moon-sized structures we have observed are irregular and dusty (e.g. comet-like) rather than solid, spherical bodies. Their absolute regularity, one passing in front of the star every 23 minutes, is a mystery we cannot currently explain.”
Researchers discovered the structures by measuring light from the white dwarf, dubbed WD1054–226, in the Milky Way about 117 light years away from us. Using a series of telescopes both on the ground and in space, including the New Technology Telescope at the La Silla Observatory in Chile, experts observed a light phenomenon they did not expect.
They noticed that every 23 minutes, with shocking consistency, the light of the star would be dimmed by a collection of 65 perfectly spaced out chunks of large debris that orbited the star on a 25-hour cycle.
Why then, researchers asked, was this light dip so regular? They can’t say for certain, but they think the most logical explanation could be the existence of a nearby planet in the Goldilocks zone that is keeping the debris on schedule.
“An exciting possibility is that these bodies are kept in such an evenly-spaced orbital pattern because of the gravitational influence of a nearby planet,” Farihi said. “Without this influence, friction and collisions would cause the structures to disperse, losing the precise regularity that is observed. A precedent for this ‘shepherding’ is the way the gravitational pull of moons around Neptune and Saturn help to create stable ring structures orbiting these planets.”
Because the orbit around the dead star was likely cleared away during its transition to a white dwarf, experts say any planet in the area that could host life likely ended up there quite recently. It should also, according to researchers, remain a livable environment for at least another billion years.
While researchers suggest the existence of this planet is a possibility, they cannot officially confirm it just yet. The planet is not directly observable, so more data on the debris and comparisons between computer models are needed before they can say for sure what cosmic body they are dealing with.
Regardless of what the future may hold for their discovery, Farihi says Friday’s study still offers an interesting window into the far-flung future of our own sun and that planets that call its orbit home.
“Since our sun will become a white dwarf in a few billion years, our study provides a glimpse into the future of our own solar system.”
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