The new space telescope is so powerful that it can detect distant asteroid belts in addition to exoplanets.
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Even with the most powerful telescopes ever created, it is challenging to see planets orbiting other stars. Stars can be seen with the unaided eye. Before 1992, some astronomers believed that our solar system might be unique and that planets might be uncommon. However, it wasn't until 1992 that astronomers successfully imaged an exoplanet, which is a planet in another solar system.
However, by the 2010s, exoplanet discoveries had become routine and there are currently over 9,000 likely or confirmed exoplanets, according to NASA. Many of these planets are larger than Jupiter due to a selection bias that favors large bodies that are close to their parent stars. Smaller bodies are much more difficult to observe; for example, there are candidate bodies for asteroids and moons, but they have yet to be confirmed.
The finding of an asteroid belt orbiting the star Fomelhaut is all the more exciting in light of this. We now have a clear understanding of the characteristics of the solar system surrounding the star Fomelhaut, which is located about 25 light years away from Earth and is one of the brightest stars in the Southern Hemisphere night sky. These new observations were made using the James Webb Space Telescope (JWST). Astronomers were surprised to find that the Fomalhaut star system is more complicated than previously believed, partly because they discovered it has an unexpectedly complicated asteroid belt, even though they had anticipated seeing many similar intricate details between our solar system and the Fomalhaut star system.
On May 8, a report in Nature Astronomy published the observations in their entirety. The outermost asteroid belt in the Fomalhaut star system has previously been observed by the Hubble Space Telescope, Herschel Space Observatory, the Atacama Large Millimeter/submillimeter Array (ALMA), and other telescopes. Astronomers can now see the inner belts for the first time thanks to JWST, which has produced a number of surprises.
There is "so much to unpack" from this one observation, according to András Gáspár, the paper's lead author and an astronomer at the University of Arizona in Tucson, who spoke with Salon.
Gáspár said, "We initially thought we would see a very narrow asteroid belt. Instead, they discovered three nested belts that stretch 150 times farther than the distance between the Sun and Earth, or about 12 million kilometers (14.3 billion miles). He continued, "There probably aren't any gas giants orbiting nearby," pointing out that the solar system contains Jupiter and Saturn. We do notice a gap, much further [out], though it roughly corresponds to our Neptune's orbit, which is a good indication that there might be an ice giant orbiting there.
Beyond the size of our own planetary system, Loeb said, "[they] reveal for the first time three nested belts in the dusty debris disk around a young hot star." The likelihood that embedded planets, which have not yet been observed, are gravitationally guiding the dust particles in the belts is high.
According to Loeb, observing waves "on the surface of a muddy pond" on Earth would suggest the presence of fish "hidden from view under the water."
Ceres, Vesta, and Pallas are just a few of the numerous small spherical bodies that make up the asteroid belt, which is thought of as a sort of "failed planet" in our own solar system. None, however, has sufficient gravity to coalesce into a larger planet. The formation of all other planets in our solar system is thought to have followed a similar process, in which debris slowly builds up to the point where it blocks the planet's orbital lane before clearing it.
However, planets also have an impact on our own asteroid belt, such as the multitude of Trojan asteroids that orbit in Jupiter's shadow. The Fomalhaut star system's outer debris disks, according to astronomers, are likely also shaped by undiscovered planets.
According to Schuyler Wolff, a team member at the University of Arizona, "We definitely didn't expect the more complex structure with the second intermediate belt and then the broader asteroid belt." The possibility of an embedded planet shaping the rings whenever an astronomer observes a gap and rings in a disk makes that structure very intriguing.
JWST's mission includes exploring the atmospheres of exoplanets that resemble Earth or, at the very least, identifying those that do. There are things to learn about the formation of our own solar system and its planets from Fomalhaut.
According to Gáspár's comments to Salon, the JWST observations show that this star system is "really chaotic" and that there is a lot of "dynamical activity going on."
These are all indications that the system is dynamically very active, according to Gáspár: "We see this inner disc that's slightly angled away from the other one." Similar to what happened in the solar system early on, there are hypotheses that our solar system underwent some dynamical reorientation at about the same age. This could be an analog to what happened in the solar system early on.
These are all indications that the system is dynamically very active, according to Gáspár: "We see this inner disc that's slightly angled away from the other one." Similar to what happened in the solar system early on, there are hypotheses that our solar system underwent some dynamical reorientation at about the same age. This could be an analog to what happened in the solar system early on.
