NASA’s James Webb Space Telescope has discovered a branch of dust shaped like a cat’s tail in the secondary circumstellar disc of the Beta Pictoris star system for the first time.
The Beta Pictoris star system (a star with a planetary system) is located just 63 light-years away in the southern constellation Pictor. The star Beta Pictoris is much younger than the sun. However, it is twice as massive and nine times more luminous than our sun.
Till now, two planets have been discovered in the Beta Pictoris star system. Planet Beta Pictoris b was discovered in 2008, and planet Beta Pictoris c was discovered in 2019.
The Hubble Space Telescope discovered two circumstellar discs around the star Beta Pictoris in 2006, where the secondary disc is inclined about 5 degrees with respect to the primary main disc.
However, recently, a team of astronomers led by Isabel Rebollido (an ESA Research Fellow) discovered a long tendril of dust (nicknamed the cat’s tail) extending from the secondary circumstellar disc of Beta Pictoris with the help of the high-resolution Mid-Infrared Instrument (MIRI) of the James Webb Space Telescope, which was previously seen.
A circumstellar disc is a debris disc of dust, gas, or planetesimals (small bodies of rock and ice) that rotates around a star. As new planets form from the circumstellar disc of a newly born star, that’s why it’s also called the protoplanetary disc.
Our sun has evolved circumstellar discs like the asteroid belt, the Kuiper belt, and the Oort cloud. The team estimates that the amount of dust within the cat’s tail is equivalent to that of a large asteroid belt spread out across 16 billion kilometers. Please remember that our asteroid belt is only 150 million kilometers, or 1 AU, across.
According to the hypothesis of Rebollido and the team, the cat’s tail is the result of a dust production event that occurred a mere one hundred years ago.
Marshall Perrin, a co-author of the study at the Space Telescope Science Institute in Baltimore, Maryland, said in a statement, “Something happens—like a collision—and a lot of dust is produced.”
“At first, the dust goes in the same orbital direction as its source, but then it also starts to spread out. The light from the star pushes the smallest, fluffiest dust particles away from the star faster, while the bigger grains do not move as much, creating a long tendril of dust.”
Christopher Stark, a co-author of the study said in a statement “Our research suggests that Beta Pic may be even more active and chaotic than we had previously thought.”
“Webb continues to surprise us, even when looking at the most well-studied objects. We have a completely new window into these planetary systems.”
So what did we learn about the Beta Pictoris star system?
Beta Pictoris is a young star that has two mysterious protoplanetary discs in two different planes and is evolving over time. The James Webb Space Telescope discovered a cat’s tail-like shape of dusty debris, which is usually not seen in discs around other stars, and this debris is produced due to the collisions between asteroids, comets, and planetesimals.
These results were presented at the 243rd meeting of the American Astronomical Society held in New Orleans, USA, from January 7–11, 2024.
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