06 September 2020 10:36

PDS 70 Moon Observation


See how three stars tore apart the dusty disk that forms the planet

Astronomers have discovered a new type of cosmic phenomenon: a misaligned planet-forming disk around a triple-star system. The misaligned disk, made of dust that will eventually clump to form planets—from our point of view—is animated immediately below. The National Radio Astronomy Observatory (NRAO) described the discovery in a recent press release, which comes via Science News. In its release, the NRAO notes two independent teams of astronomers used the Atacama Large Millimeter/submillimeter Array (or ALMA) to make the discovery. The two teams of astronomers, led by Jiaqing Bi at the University of Victoria in Canada, and Stefan Kraus from the University of Exeter in the U.K., discovered the misaligned disk around a trio of stars.

gw orionis

Astronomers found the trio of stars, GW Orionis, back in 1949; it's only now, however, that astronomers have found evidence for the misshapen disk. As the below European Southern Observatory video notes, Bi and his team used near infrared and submillimeter telescopes to detect the warped, planet-forming disk. Disk tearing is the process by which the planet-forming disk develops rings that have varied orientations in regards to their rotational axis. "In our images, we see the shadow of the inner ring on the outer disk," Kraus said in the NRAO release. That shadow, Kraus added, allowed the astronomers to measure the precise shape of the ring of dust casting it.


"We were surprised to see the strong misalignment of the inner ring," Bi said in the NRAO release. "But the strange warp in the disk is confirmed by a twisted pattern that ALMA measured in the gas of the disk," the astronomer added. The other is that a newborn planet could be warping the disk thanks to its own gravitational pull. In fact, Kraus said in the NRAO release that the inner ring contains enough dust to build 30 Earths. And if the astronomers even find one, it'll be the first time a planet's ever been observed around a trinary star system.


What do you think about this strange planet-forming disk of dust? Do you think astronomers will indeed find planets in this triple-star system? A group of astronomers have found the first direct evidence that groups of stars can rip apart their disk that forms the planets, causing it to be deformed. A new study, published in the journal Science, suggests that exotic planets could form oblique rings in curved discs around multiple stars. These results were made possible by observations with the European Southern Observatory's Very Large Telescope (ESO VLT) and the Atacama Large Millimeter/Submillimeter Array (ALMA).


But this does not apply to all-star systems, especially to the disks that form planets around several stars, as the object of new research – the GW Orionis star system. This system, located just over 1,300 light-years away in the constellation Orion, consists of three stars and a warped, ruptured disk surrounding them. "Our images show an extreme case where the disk is not flat at all, but deformed and has a displaced ring that has broken off from the disk," says Stephen Kraus, professor of astrophysics at the University of Exeter in the UK. "We found that the three stars do not orbit in the same plane, but that their orbits are offset from each other and from the disk," says Alison Young of the Universities of Exeter and Leicester and a team member. They also observed the system with the SPHERE instrument on VLT ESO and ALMA, in which ESO is a partner, and were able to image the inner ring.

An international team of researchers from the UK, Belgium, Chile, France, and the United States combined their exhaustive observations with computer simulations to understand what happened to the system. For the first time, they were able to clearly link the observed inconsistencies with a theoretical "disk rupture effect," which suggests that the conflicting gravitational pull of stars in different planes can deform and break their disks. Their modeling showed that the misalignment of the orbits of the three stars can lead to the fact that the disk around them breaks into separate rings, which they see in their observations. The observed shape of the inner ring also matches the predictions of numerical simulations of how the disk will rupture. Future observations with ELT and other ESO telescopes could help astronomers fully uncover the nature of GW Orionis and reveal young planets forming around its three stars. We usually define a solar system by the structure that has a single star in the center and planets revolving around it. The GW Orionis (or GW Ori) solar system from the Orion constellation is the new attraction point for astronomers, as it's home to not one, but three stars. Two suns from the GW Orionis are orbiting one another at the center, while a third star is swirling around the other two. The solar system features three bright rings of planet-forming dust, and astronomers had been using them to detect GW Orionis. Young planet existing under the dust? Closer observations of astronomers reveal that a young planet could be forming itself beneath the solar system's dust. There are several clues that point to the possible existence of a planet: one of them is the wobbling around of the system's inner ring. Our simulations show that the gravitational pull from the triple stars alone cannot explain the observed large misalignment [in the rings], We think that the presence of a planet … has likely carved a dust gap and broken the disk [where the inner and outer rings meet]. Stefan Kraus, professor of astrophysics at the University of Exeter in the U.K, declared: The inner ring contains enough dust to build 30 Earths, which is sufficient for a planet to form in the ring, The claim of the existence of a planet within GW Orionis still needs further observations for confirmation. If the answer is positive, the planet will become the only known one that orbits three stars simultaneously. Bengaluru: Astronomers have observed, for the first time, a group of stars tearing apart their planet-forming disc. The force of these stars leaves behind material in the form of twisted rings, and the astronomers suggest that this could potentially produce planets with multiple star systems, like the desert-planet Tatooine in the Star Wars movie series, which had two suns. The study was a collaboration between researchers from the UK, Belgium, Chile, France and the US, who studied the three newborn stars in the GW Orionis system using the AMBER (Astronomical Multi-BEam combineR) and GRAVITY instruments on the European Southern Observatory's (ESO) Very Large Telescope (VLT) in Chile. The findings of the study, which was led by Stefan Kraus from the UK's University of Exeter, were published Friday in the journal Science. Star and planet formation Young stars and star systems form when a cloud of dust and gas collapses under its own gravity, leading to spinning material that eventually forms a disc-like shape. This material surrounding the increasingly gravitationally powerful core, which will eventually become a star, is called the circumstellar disc. This will eventually form planets and other bodies such as asteroids and comets. But in some star systems, multiple nuclei of stars form, which leads to gravitational confusion and structural disruption of the disc. Astronomers had never observed such a process occurring before (although we've observed plenty of multi-star systems). Theoretical modelling suggests that when multiple gravitationally powerful stars form from the same material, the disc should bend and twist, eventually breaking into concentric, misaligned rings. The observation of the newly forming GW Orionis system in the constellation of Orion confirms these theories. The star system has three stars and a deformed disc around them, which holds a misaligned ring in the middle, closer to the stars. "Our images reveal an extreme case where the disc is not flat at all, but is warped and has a misaligned ring that has broken away from the disc," said Kraus, a professor of astrophysics at the University of Exeter. The ring was detected by observing its shadow on the rest of the disc. The astronomers state in their paper that multiple rings could potentially form in systems like these elsewhere. Planet-forming potential The research also shows that the inner ring contains material, primarily dust, worth 30 times the mass of Earth. Astronomers think that this gives the system ample opportunity to produce at least one planet. "Any planets formed within the misaligned ring will orbit the star on highly oblique orbits and we predict that many planets on oblique, wide-separation orbits will be discovered in future planet imaging campaigns," said the study's co-author Alexander Kreplin. This is especially so because the orbits of the three stars, which are going around each other, are also misaligned with respect to each other's orbital plane and the outer circumstellar disc. The planets are likely to also be in retrograde orbits — that is, revolving in the direction opposite to the star's rotation. Scientists have already detected more than 200 stellar systems with multiple stars and planets. But scientists have not, until now, observed planets at such an early stage of its formation. Further observations could strengthen our understanding and aid in the detection of science fiction-like exoplanets. Also read: India's AstroSat telescope discovers one of the earliest galaxies to have formed Why news media is in crisis & How you can fix it You are reading this because you value good, intelligent and objective journalism. For us to continue bringing quality journalism, we need readers like you to pay for it. The research focuses on a trio of stars about 1,300 light years away in a system called GW Orionis, in the constellation of Orion. They are surrounded by an immense disc of dust — the raw material for new planets — and scientists believe the conditions are right to create a world rather like Tatooine, which appeared in Star Wars, although this one would have three "suns" rather than two. The inner disc around GW Orionis is perfect for a Star Wars-style planet EUROPEAN SOUTHERN OBSERVATORY

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