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Fomalhaut – understand “the mouth of the fish” – is the brightest star of a small constellation visible from Earth, southern Pisces. A young star only 25 light years away from our planet. It is known to astronomers and even amateurs for orbiting Fomalhaut b, the first exoplanet to be photographed. It was from the Hubble Space TelescopeHubble Space Telescope, in 2008, before it just…disappeared!
The missing exoplanet Fomalhaut b is actually a giant collision!
New data from the James Webb Space Telescope (JWST) seems to want to confirm that this exoplanet was in fact not one. That the object captured by Hubble was more likely the remnants of a collision between planets that formed a cloud of dust. A cloud ‘fading and growing’ in the new images astronomers have examined.
It was precisely the debris disks that the researchers discovered around Fomalhaut in the 1980s that prompted them to study this star intensively. This time dust belts created by collisions between asteroid- or comet-type bodies. The Hubble Space Telescope and Herschel Space Observatory and the Atacama Large Millimeter/submillimeter Array (Alma) had already taken sharp images of the outermost belt. “These instruments have taught us a lot about how these disks form and evolve,” said Schuyler Wolff, a researcher at the University of Arizona (USA), in a NASA press release.
But today it is the James Webb Space Telescope that offers researchers the opportunity to observe the structure of Fomalhaut’s inner belts. Thanks to its ability to “physically dissipate the thermal glow of the dust in these regions”. And what the JWST has just revealed to astronomers is that the dusty structures around Fomalhaut are much more complex and dynamic than the asteroids and dust belts — the Kuiper BeltKuiper Belt — that we’ve found in our solar system.
A planetary system around Fomalhaut?
Researchers note the existence of three interlocking belts stretching up to 23 billion kilometers from the star. This corresponds to 150 times the distance between our earth and the sun. With an outer belt that looks very similar to our Kuiper belt. Twice as wide though. But what’s really new is the description astronomers give of the belt closest to the star and an asteroid belt, a middle asteroid belt. The latter appears inclined at 23° to the rest of what revolves around Fomalhaut.
“There’s probably a really interesting planetary system around Fomalhaut”
“I don’t think it’s going too far to say that there’s probably a really interesting planetary system around Fomalhaut,” notes George Rieke, manager of the mid-infrared instrument (MiriMiri) at the James Miri Webb Space Telescope. For astronomers have long imagined that debris disks grow after planets form, when small bodies like asteroids collide and pulverize their surfaces into giant dust clouds, all sculpted by planet-generated gravitational forces, as is the case in our solar system , where Jupiter orbits Jupiter’s asteroid belt and where the inner edge of the Kuiper Belt was carved by Neptune, while its outer edge could be carved by the famous and always elusive Planet X.
Thanks to the JWST, the researchers were also able to observe a structure they dubbed “the great dust cloud,” possible evidence that a collision between two protoplanetary bodies took place in Fomalhaut’s outer ring — but it could also be a distant object that was seen through the debris, further observation should help determine this. A different collision than the one mentioned to explain the strange disappearance of Fomalhaut b. And further proof that the Fomalhaut system is potentially complex and active.
Exceptional image of a dust ring around a star
As part of an extensive search program for evidence of the existence of extrasolar planets, the Hubble Space Telescope has achieved a major feat by obtaining the most detailed image ever of a particularly narrow dust ring around the Fomalhaut star. This image suggests that a currently unseen planet could deform it, giving away its presence. Especially since computer simulations computer simulations confirm its existence due to disturbances affecting the star.
Article by Rémy DecourtRémy Decourt published on 07/16/2005
Scientists confirm that they could have seen the planet even if it had been five times more massive than Jupiter. More observations are planned this summer to complete the picture. (the ring is too big to stay in the camera’s field, which explains the missing part) and color analyzes of the ring are also planned to determine its physical properties and composition.
Some like to compare this ring to the Kuiper Belt of the solar system. This belt consists of the remains of the formation of the planets. These are blocks of matter that are not aggregated with other planetoids.
The choice of formal skin (HD 216956) is not trivial. It is one of the nearest stars surrounded by a disk of dust and gaseous gas. In particular, its position relative to Earth allows Hubble to observe it well, which is not the case, for example, with better-known stars also surrounded by such a disk, such as Beta Pictoris and from Au microscopy. They are presented under the rim, which makes their observation very difficult.
But observing Fomalhaut is not easy. The star is very bright and therefore hides the details of its disc structure. Hubble therefore used the ACS’ Coronagraphecoronographe, which makes it possible to hide a star’s light and see the equipment surrounding it. The resulting image has high sensitivity and resolution. In the case of Fomalhaut, the Hubble images have a Resolution of about 0.5 AUUA or 75 million km.
Fomalhaut is close to the Sun, but is only 25 light-years away twice as massive as our star and not very old, only 200 million years, one twentieth the age of the sun. It is the brightest star in the Pisces constellation.
When we refer to the solar system, this period corresponds to the great bombardmenta period that lasted more than 700 million years after the formation of the sun and during which 14 million objects hit the earth, enriching it with various materials. This period is exciting because it marks the transition between the birth of the planets and their “final” state. The moon was bombarded by over 1 million objects, creating the craters visible today. Comets brought large amounts of water to Mars, and all of the planets’ atmospheres were greatly altered by this episode. Note that there are no fossils or evidence of this period on Earth, which has seen many upheavals on the surface throughout its history.
The Hubble image clearly shows a narrow ring, only 25 AU wide, starting at a distance of 133 AU from its star and extending to 159 AU. In comparison, the Kuiper Belt is 30 AU from the Sun and extends as far as 50 AU from the Sun (well beyond PlutoPluto’s orbit). But while the star’s disk conforms to the Kuiper Belt, its diameter is four times larger.
The edge of the cloud is very sharp and resembles the edge of a knife blade. It’s basically cut. It is similar to the rings of Saturn where we observe very fine structures maintained by small shepherd satellites. The ring does not appear centered on the star but over an area of 2.25 billion km, which seems to take the lead. Kepler’s laws of motion state that objects that describe elliptical orbits are always offset from the geometric center of the ellipse. In the current case, This offset implies a planet traversing a highly elliptical orbit which also sweeps up and absorbs the dust that makes up the disk, much like Neptune and the larger planets of our solar system sucked up the debris that formed the primitive disk of dust that surrounded our Sun, leaving behind a distant ring of rocky debris (the Kuiper Belt ) .