Dr. Christopher Stark and colleagues at NASA Goddard Space Flight Center present new coronagraphic images from Earth NIRCam (near infrared camera) and mm (Mid-Infrared Instrument) instruments aboard the NASA/ESA/CSA James Webb Space Telescope reveal never-before-seen structures in the debris disk around the young star Beta Pictoris.
Pictoris Beta is a young planetary system located approximately 63 light-years from Earth.
Estimated to be only 20 million years old, it is known to be home to the gas giant Beta Pictoris b.
In the new study, Stark and co-authors used Webb's NIRCam and MIRI instruments to investigate the composition of Beta Pictoris' primary and secondary debris disks.
“Pictoris Beta is an all-inclusive debris disk. It has a very bright and close star that we can study well, a multicomponent disk, an exocomet, and two imaged “There is a complex circumstellar environment that includes exoplanets,” the Astrobiology Center said. astronomer Isabel Rebolido;
“There have been ground-based observations in this wavelength range before, but this feature was not detected because we did not have the sensitivity and spatial resolution of the current web.”
Even with Webb, peering into Beta Pictoris in the right wavelength range was crucial to detecting the never-before-seen dust trail, which resembles a cat's tail. This is because it only appeared in MIRI data.
Webb's mid-infrared data also revealed differences in temperature between Beta Pictoris' two disks. This is probably due to differences in composition.
“We didn't expect Webb to reveal that there are two different types of material surrounding Beta Pictoris, but MIRI clearly shows that the material in the secondary disk and cat's tail is hotter than the main disk. Dr. Stark said.
“The dust that forms its disk and tail must be so dark that it is not easily visible at visible wavelengths, but it glows in the mid-infrared.”
To explain the higher temperatures, astronomers speculated that the dust could be a porous “organic refractory” similar to the material found on the surfaces of comets and asteroids in our solar system. .
For example, preliminary analysis of material collected from the asteroid Bennu by NASA's OSIRIS-REx mission revealed very dark, carbon-rich material similar to what MIRI detected on Beta Pictoris.
But big questions still remain. What explains the shape of the cat's tail, a uniquely curved feature unlike those seen in disks around other stars?
Researchers modeled various scenarios to mimic a cat's tail and uncover its origins.
Although more research and experiments are needed, the researchers offer a strong hypothesis that cat tails are the result of a dust-producing phenomenon that occurred just 100 years ago.
“Something happens, like a collision, and it creates a lot of dust,” says Dr. Marshall Perrin, an astronomer at the Space Telescope Science Institute.
“At first, the dust follows the same trajectory as its source, but then it starts to spread out.”
“Light from the star pushes the smallest, fluffiest dust particles away from the star faster, while larger particles move less, creating long dust tendrils.”
“The characteristics of a cat's tail are so unusual that it has been difficult to reproduce the curvature in mechanical models,” Dr. Stark said.
“Our model requires dust to be pushed out of the system very quickly, which also suggests it is made of organic refractory materials.”
“The model we have recommended explains the sharp angle of the tail away from the disk as a simple optical illusion.”
“Our perspective, combined with the curved shape of the tail, creates the observed tail angle, but in reality, the arc of material is only pointing away from the disk at a 5-degree inclination.”
“Considering the brightness of the tail, we estimate that the amount of dust in the cat's tail is equivalent to a large main-belt asteroid spanning 10 billion miles.”
Recent dust production events within Beta Pictoris' debris disk may also explain the newly observed asymmetric spreading of the tilted inner disk, shown in the MIRI data and only seen on the opposite side of the tail. there is.
“Our study suggests that Beta pictris may be even more active and chaotic than previously thought,” Dr. Stark said.
“The Webb continues to amaze us even when looking at the most well-studied celestial objects. We have a whole new window into these planetary systems.”
christopher stark other. 2024. A new view of JWST's Beta Pictris suggests recent bursts of dust production from an eccentric, tilted secondary debris disk. AAS243Abstract #4036