Nearly twenty years ago, astronomers observed a huge cloud of fine dust particles around a young star just 63 light-years away from Earth. From recent observations of the Webb Space TelescopeHowever, the dust cloud had mysteriously disappeared. Now a new paper suggests that the dust cloud may have been caused by a violent event that pulverized large celestial bodies and scattered their remains across the continent. Beta Pictoris galaxy.
Using new data from Webb, a group of scientists noticed significant changes in the energy signatures emitted by dust grains around Beta Pictoris, with particles disappearing completely. By comparing the Webb data with older observations recorded by the Spitzer Space Telescope in 2004 and 2005, scientists suggested that a cataclysmic collision between large asteroids occurred about twenty years ago, causing the celestial bodies to break apart into fine dust particles smaller than powdered sugar. The dust likely cooled as it moved away from the star. Therefore, it no longer radiates the same thermal signatures first observed by Spitzer. The new findings were presented Monday at 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. This young star system is home to the first debris disk ever observed around another star, and is notable for its proximity and brightness.
When Chen got twelve hours of observations with Webb, she wanted to go back and look at the same galaxy, Beta Pictoris, that had intrigued her all these years. This time, however, the star system didn’t look so familiar. “I thought, ‘oh my god, the features are gone,’” Chen told Gizmodo. “Is this real? And if so, what happened?”
Through the Webb observations, Chen, who led the new study, and her team focused on the heat radiated by crystalline silicates (minerals often found around young stars) and found no traces of the particles previously discovered in 2004 and 2005 were observed.
“Whenever astronomers look at the sky and see something, we always assume that everything is in a steady state, that it is not changing,” Chen said. “The reason we think that is because if you think about the specific moment you’re looking at, it’s very short compared to how old these objects are. So we think that the chance that you will come across something interesting is very small. ”
That was apparently not the case for Beta Pictoris, a galaxy believed to be between 20 and 26 million years old. That’s relatively young compared to our own solar system, which is roughly 4.6 billion years old. In their early years, galaxies are more unpredictable, because terrestrial planets are still forming through collisions with giant asteroids.
Therefore, the observed changes in Beta Pictoris were quite significant. According to astronomers, the dust cloud was 100,000 times larger than the asteroid that killed the dinosaurs. This suggests that the collision that may have led to the formation of this enormous cloud likely involved an asteroid about 1.5 meters in size Vestathe second heaviest body in the main asteroid belt with a diameter of 530 kilometers.
The dust was then spread 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 showed that the dust had disappeared and not been replaced, indicating a violent collision.
“We think that these kinds of large collisions must have occurred in our solar system when it was about the same age as part of the formation process of terrestrial planets,” Chen says. “We can look at ancient Earth surfaces of the moon, Mars and Mercury and they all have craters, which tells us that impacts were much more common when our solar system was young.”
The recent observations of Beta Pictoris allow scientists to investigate whether the formation process that formed our solar system is rare or common in the universe, and how these early collisions affect the habitability of a given galaxy.
“This giant collision happens and it creates a cloud of dust that propagates outward from the star,” Chen said. “You might imagine that there is a possibility that this dust cloud, as it traveled toward the planetary system, also encountered the planets and could have rained dust on their planetary atmospheres.”
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