Webb's infrared eye reveals a strange “cat's tail”-like dust structure in Beta pictoris

New observations in infrared light indicate that a massive collision occurred recently

Since the 1980s, the planetary system around the star Beta Pictoris has continued to fascinate scientists. Even after decades of study, they still hold surprises.

NASA's James Webb Space Telescope It has opened an exciting new chapter in the Beta Pic story, which includes new details about the formation of debris disks and a never-before-seen dust trail that resembles a cat's tail. A team of astronomers hypothesizes that this feature is a relatively recent addition to the planetary system – a tail that is not as old as time.

NASA's James Webb Space Telescope imaged the Beta Pictoris star system. Webb's MIRI (Mid Infrared Instrument) enabled a team of astronomers to investigate the composition of Beta Pic's primary and secondary debris disks – the latter feature previously detected by the Hubble Space Telescope.
Unexpectedly, Webb's infrared capabilities detected a new feature of the Beta Pic system: a sinuous branch of dust resembling the shape of a cat's tail. This tail, which is only observable in the MIRI data, extends from the southwestern portion of the secondary debris disk and is estimated to extend 10 billion miles.
The dust that forms the tail may be similar to the material found on the surfaces of comets and asteroids in our solar system. More analysis is needed to understand the origins of the cat's tail, although the team believes a dust-producing event – such as collisions between asteroids, comets or planetesimals – is responsible.
Image credit: NASA, ESA, CSA, STScI, Christopher Stark (NASA-GSFC), Kellen Lawson (NASA-GSFC), Jens Kammerer (ESO), Marshall Perrin (STScI)

The Webb Space Telescope detects a dusty 'cat's tail' in the Beta Picturis system

Beta Picturis, a young planetary system located just 63 light-years away, continues to interest scientists even after decades of in-depth study. It has the first dust disk ever imaged around another star, a disk of debris resulting from collisions between asteroids, comets and small planets. Notes from NASA Hubble Space Telescope Reveal a Second debris disc In this system, it is tilted with respect to the outer disk, which was first seen. Now, a team of astronomers using NASA's James Webb Space Telescope to image the Beta Pictoris system (Beta Pic) has discovered a new, never-before-seen structure.

The team, led by Isabel Rebolledo of the Astrobiology Center in Spain, used Webb's NIRCam (near-infrared camera) and MIRI (mid-infrared instrument) to investigate the composition of the primary and secondary debris disks previously detected by Beta Pic. The results exceeded their expectations, revealing a sharply tilted dust branch, shaped like a cat's tail, extending from the southwestern part of the secondary debris disk.

“Beta Pictoris is a debris disk that has it all: it has a really bright, close star that we can study well, a complex stellar oceanic environment with a multi-component disk, exocomets, and a couple of imaged exoplanets,” Rebolledo said. Lead author of the study. “Although there were previous observations from Earth in this wavelength range, they did not have the sensitivity and spatial resolution that we have now with Webb, so they did not detect this feature.”

This is an animation depicting the formation of a cat's tail, as hypothesized by a team of astronomers. This structure, visible in the southwestern part of Beta Pic's secondary debris disk, is estimated to extend 10 billion miles.

Scientists hypothesize that the cat's tail is the result of a dust-producing event – ​​such as an impact – that occurred just a hundred years ago. Initially, the resulting dust follows the same orbital direction as its source, and then begins to spread. Starlight pushes smaller, finer dust particles away from the star faster, while larger grains don't move as much, creating a dust trail.

From an edge perspective, the sharp tilt of a cat's tail is an optical illusion. Our perspective combined with the curvature of the tail creates the observed angle, whereas in reality, the dust tendrils only leave the disk at an inclination of five degrees.

Image credit: NASA, ESA, CSA, STScI, Ralph Crawford (STScI)

The star image was enhanced using Webb

Even with the Webb, or JWST, looking at the Beta Pic in the right wavelength range — in this case, mid-infrared — was crucial to detecting the cat's tail, as it only appeared in the MIRI data. Webb's mid-infrared data also revealed temperature differences between Beta Pic's two disks, which is likely due to differences in composition.

“We didn't expect Webb to reveal that there are two different types of material around Beta Pic, but MIRI has clearly shown us that the material from the secondary disk and the cat's tail is hotter than the main disk,” said Christopher Stark, one of the study's co-authors. – Study author at NASA's Goddard Space Flight Center in Greenbelt, Maryland. “The dust that forms this disk and tail must be very dark, so we can't see it easily at visible wavelengths — but in the mid-infrared, it's glowing.”

To explain the hotter temperature, the team concluded that the dust may be a highly porous “thermal organic material,” similar to the material found on the surfaces of comets and asteroids in our solar system. For example, a preliminary analysis of material taken from the asteroid Bennu by NASA Osiris Rex The mission found it to be very dark and carbon-rich, just like what MIRI discovered in Beta Pic.

Annotated version of an image of Beta Pictoris taken by Webb's MIRI (mid-infrared instrument). A coronagraph (a black circle and two small discs) was used to block the light of the central star. Some features are highlighted and classified.
A white line is drawn above the orange main debris disk and is called the “main disk level”. The thin blue-green disc is tilted about five degrees counterclockwise relative to the orange primary disc and is marked by a blue-green line called the “extended secondary disc.” Some gray matter collected near the center forms a curved feature in the upper right, which is marked by a yellow line called the “cat's tail.”
The scale bar shows that the Beta Pic disks span hundreds of astronomical units (AU), where one AU represents the average distance between the Earth and the Sun. (In our solar system, Neptune orbits at a distance of 30 AU from the Sun.) In this image, light at 15.5 microns is cyan and 23 microns is orange (filters F1550C and F2300C, respectively).
Image credit: NASA, ESA, CSA, STScI, Christopher Stark (NASA-GSFC), Kellen Lawson (NASA-GSFC), Jens Kammerer (ESO), Marshall Perrin (STScI)

The puzzling onset of the tail requires future research

However, a big question remains: What could explain the cat's tail shape, a uniquely curved feature unlike what is seen in disks around other stars?

Rebolledo and the team designed different scenarios in an attempt to mimic a cat's tail and reveal its origins. Although more research and testing is needed, the team presents a strong hypothesis that the cat's tail is the result of a dust-producing event that occurred only a hundred years ago.

“Something happens — like a collision — and a lot of dust is produced,” says Marshall Perrin, co-author of the study at the Space Telescope Science Institute in Baltimore, Maryland. “At first, the dust travels in the same orbital direction as its source, but it also begins to spread out. Light from the star pushes smaller, finer dust particles away from the star faster, while larger grains don't move as much, creating long tendrils of dust.” .

“The feature of a cat's tail is quite unusual, and the curvature was difficult to reproduce in a dynamic model,” Stark explained. “Our model requires dust that can be pushed out of the system very quickly, which again suggests that it is made of refractory organic matter.”

Illustrative image of the Beta Pictoris star system taken with Webb's MIRI (Mid Infrared Instrument), with compass arrows, scale bar, and color key for reference.
The north and east compass arrows show the direction of the image in the sky. Notice that the relationship between north and east in the sky (as seen from below) is inverted relative to the directional arrows on the Earth's map (as seen from above).
The scale bar is labeled in astronomical units and arc seconds. One AU is the average distance between the Earth and the Sun. (In our solar system, Neptune orbits at a distance of 30 astronomical units from the Sun.) Arc seconds are a measure of angular distance in the sky. One arcsecond is equal to 1/3600 of one degree of arc. (The Moon's angular diameter is about 0.5 degrees.) The actual size of an object covering one arcsecond in the sky depends on its distance from the telescope.
This image shows invisible mid-infrared wavelengths translated into the colors of visible light. The color key shows which MIRI filters were used when collecting the light. The color of each filter name is the color of visible light used to represent the infrared light passing through that filter.
Image credit: NASA, ESA, CSA, STScI, Christopher Stark (NASA-GSFC), Kellen Lawson (NASA-GSFC), Jens Kammerer (ESO), Marshall Perrin (STScI)

The team's preferred model explains the sharp angle of the tail away from the puck as a simple optical illusion. Our perspective with the curved shape of the tail creates the observed angle of the tail, while in reality, the arc of the material only departs with an inclination of five degrees. Taking into account the brightness of the tail, the team estimates that the amount of dust inside the cat's tail is equivalent to a large main asteroid belt spread across 10 billion miles.

A recent dust production event within Beta Pic's debris disks could also explain the newly observed asymmetric extension of the tilted inner disk, as shown in the MIRI data and only seen on the side opposite the tail. Recent impact dust production could also be responsible for a feature previously observed by Atacama Large Millimeter/Submillimeter Array in 2014: A mass of carbon monoxide (CO) located near a cat's tail. Since the star's radiation must break down the carbon dioxide within about a hundred years, the concentration of gas still present could be surviving evidence of the same event.

“Our research suggests that Beta Pic may be more active and chaotic than we previously thought,” Stark said. “The James Webb Space Telescope continues to surprise us, even when looking at well-studied objects. We have a whole new window on these planetary systems.”

These results were presented in a press conference at the 243rd meeting of the American Astronomical Society in New Orleans, Louisiana.

The observations were taken as part of the 1411 Assured Time Monitoring Programme.

The James Webb Space Telescope is the world's leading space science observatory. Webb solves the mysteries of our solar system, looks beyond the distant worlds around other stars, and explores the mysterious structures and origins of our universe and our place in it. WEB is an international program led by NASA with its partners the European Space Agency (ESA).European Space Agency) and the Canadian Space Agency.