Almost 20 years ago, astronomers observed a massive cloud of fine dust particles around a young star located just 63 light-years from Earth. In recent observations from Webb Space Telescopehowever, the cloud of dust mysteriously disappeared. Now, a new paper suggests that the dust cloud may have been caused by a violent event that crushed large celestial bodies and spread their debris across the globe. The Beta Pictoris star system.
Using the new data from Webb, the team of scientists noticed significant changes in the energy signatures emitted by dust grains found around Beta Pictoris, with the particles disappearing entirely. By comparing Webb’s data with older observations captured Spitzer Space Telescope in 2004 and 2005, scientists suggest that about 20 years ago there was a cataclysmic collision between large asteroids that shattered the celestial bodies into fine dust particles smaller than powdered sugar. The dust likely cooled as it moved away from the star, which is why it no longer emits the same thermal features first observed by Spitzer. The new findings were presented Monday during the annual meeting of the American Astronomical Society in Madison, Wisconsin.
Christine Chen, an astronomer at the Space Telescope Science Institute and Johns Hopkins University, first observed Beta Pictoris in 2004 using the Spitzer Space Telescope. The young star system is home to the first debris disk ever imaged around another star, and is notable for being close and bright.
When Chen got 12 hours of observing with Webb, she wanted to go back and look at the same star system, Beta Pictoris, that had fascinated her all those years. This time, however, the star system didn’t look so familiar. “I was like, oh my god, the features are gone,” Chen told Gizmodo. “Is it real? And if so, what happened?”
Using Webb’s observations, Chen, who led the new study, and her team focused on the heat emitted by crystalline silicates—minerals commonly found around young stars—and found no trace of the particles previously observed in 2004 and 2005.
“Whenever astronomers look at the sky and see something, we always assume that everything is in a steady state, that it’s not changing,” Chen said. “The reason we think that is because when you think about the specific moment that you’re looking at, it’s very short compared to how old these objects are, so we just think that the chances of capturing something interesting , is very small.”
That apparently wasn’t the case for Beta Pictoris, a star system thought to be 20 to 26 million years old. This is relatively young compared to our own solar system, which is roughly 4.6 billion years old. During their early years, star systems are more unpredictable as terrestrial planets continue to form through giant asteroid collisions.
Therefore, the changes observed in Beta Pictoris were quite significant. The dust cloud was 100,000 times larger than the asteroid that killed the dinosaurs, according to astronomers. This suggests that the collision that may have caused this massive cloud to form probably involved an asteroid the size of it Vestthe second most massive body in the main asteroid belt, stretching over 329 miles (530 kilometers) in diameter.
The dust was then scattered outward by radiation from the star, and the dust near the star heated up and emitted thermal radiation that was identified by Spitzer’s instruments. Webb’s new observations revealed that the dust disappeared and was not replaced, indicating a violent collision.
“We think that large collisions like this must have occurred in our solar system when it was of a similar age as part of the formation process of the terrestrial planets,” Chen said. “We can look at the old Earth surfaces of the Moon, Mars and Mercury, and they all have craters on them, which tells us that impacts were much more common when our solar system was young.”
Through recent observations of Beta Pictoris, scientists can investigate whether the formation process that formed our solar system is rare or more common throughout the universe, and how these early collisions affect the habitability of a given star system.
“If there’s this giant collision and there’s a cloud of dust that’s going to spread away from the star,” Chen said. “You can imagine that there is some possibility that this dust cloud, as it traveled into the planetary system, also hit the planets and could have rained dust down into their planetary atmospheres.”
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