Latest news with #planetformation
Yahoo
38 minutes ago
- Science
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What would happen if you tried to land on a gas giant?
Our solar system contains three types of planets. Between the four terrestrial planets–Mercury, Venus, Earth, and Mars–and the distant ice giants of Neptune and Uranus, sit two gas giants: Saturn and Jupiter. These planets are mostly composed of hydrogen and helium gas. Researchers now appreciate that gas planets are more complex than first thought. New findings have implications for our understanding of how these planets formed and will help design future missions to potentially visit them. Gas giants originate from one of two processes. The first method is called core accretion, explains Ravit Helled, a professor of theoretical astrophysics at the University of Zürich. This starts with the birth of a new star, when molecular clouds collapse under gravitational pressure. Whorls of gas–called protoplanetary disks–start to spin around these new stars. Within these gas disks will be heavier particles–dust, rock, or any elements heavier than helium. These particles can clump together and then suck in gas from the surrounding disk, forming a giant planet mainly composed of gas. A second method that may form gas giants called disk instability–this is a newer theory that still causes some controversy among planetary theorists. According to this idea, when massive protoplanetary disks cool down, they become unstable and can produce clumps of rock and gas that evolve into gas giants. Importantly, this proposed formation process happens much more quickly than core accretion. Helled says that Saturn and Jupiter likely formed via core accretion, but that disk instability may 'explain very massive planets at large orbits or giant planets around small mass stars.' Regardless of how they form, the structure of gas giants is nothing like that of terrestrial planets like Earth. Jupiter and Saturn don't have a surface in the same way Earth does. Instead, their atmosphere simply gets thinner until there isn't enough density left to call the surrounding air part of the planet anymore. 'There is no location where you can say, okay, this is where the planet stops,' says Helled. A spaceship attempting to 'land' on Jupiter's 'surface' would have to overcome some significant obstacles. Once you enter the cloud of gas that roughly marks the beginning of a giant like Jupiter, temperature and pressure steadily increase as your head toward the planet's core, and gaseous hydrogen and helium morph into liquid form. While our solar system's gas giants are far from the sun, the core of a gas giant is likely to be incredibly hot–Jupiter's is estimated at around 43,000 degrees Fahrenheit. You'd also have to pass through the thick clouds of ammonia found in Jupiter's upper atmosphere. If you make your ship from tough stuff–tougher than any known substance on Earth–that could survive these conditions, it might make it to a gas giant's core. What it would find there in the alien murk is still unclear. 'For decades, it was assumed that there was a defined core,' says Helled. Recent probe missions, like Juno and Cassini, have orbited Jupiter and Saturn, respectively. The information these probes sent back has changed that view. 'We now think that they have what we call fuzzy or diluted cores,' says Helled. This means that there isn't a clear transition point between the upper layers of liquid gas and liquid hydrogen and helium and the planet's core. In truth, Juno and Cassini's data has revolutionized our understanding of these planet's structures. Helled explains that they likely have complex heat and composition gradients. Jupiter is famously wracked with massive storms, like the Great Red Spot, which produces winds up to 425 mph (640 km/h). Some of these shifts can produce dramatic phenomena. Jupiter and Saturn likely have regions in which helium gas separates from hydrogen. Here, the helium becomes a rain of droplets that pour towards the planet's core. These insights can reveal more about our solar system's giants, as well as similar planets outside our solar system. 'Now we realize that some of the simple assumptions that we've made to model these planets are wrong, and we need to modify the models,' says Helled. This story is part of Popular Science's Ask Us Anything series, where we answer your most outlandish, mind-burning questions, from the ordinary to the off-the-wall. Have something you've always wanted to know? Ask us.
Yahoo
14-06-2025
- Science
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A tiny star gave birth to an absolute giant. Scientists are puzzled.
Astronomers have discovered a world outside the solar system about 240 light-years away in space that is a freak of nature. Somehow, a little red dwarf star only one-fifth the size of the sun gave birth to an enormous baby — an exoplanet that is a little larger than Saturn, although it weighs about half as much as our ringed gas giant. Discovered in a sweeping investigation of NASA's Transiting Exoplanet Survey Satellite data, this world, TOI-6894 b, and its host star have set a new record for their incongruous sizes. Together they are the smallest known star to have an orbiting giant planet. If there were a Guinness Book of Galactic Records, this one would have a landslide victory for the titleholder. The star, TOI-6894, is just 60 percent the size of the next smallest star with such a planet. The pair's existence breaks all the rules of what scientists know about planet formation. "We don't really understand how a star with so little mass can form such a massive planet!" said Vincent Van Eylen, a researcher at the University College London, in a statement. "By finding planetary systems different from our solar system, we can test our models and better understand how our own solar system formed." SEE ALSO: The Webb telescope found something exceedingly rare around a dying star NASA's TESS mission — short for Transiting Exoplanet Survey Satellite — was designed to find new worlds as they pass in front of their host stars. Credit: NASA illustration Edward Bryant, who led the research team, found the behemoth first by poring over TESS space telescope data of over 91,000 small red dwarfs, aka M-type stars. Then he used the European Southern Observatory's Very Large Telescope in Chile to reveal TOI-6894b. According to How to Make a Really Humongous Planet 101, it should be difficult — nearly impossible — for stars this tiny to do this. That's because the disks of gas and dust swirling around young stars are the construction materials for planets. Small stars tend to have smaller and lighter disks. Gas giants like our own Jupiter or Saturn need a lot of stuff to form their cores. They then are able to attract a lot more gas quickly from their surroundings to collect an atmosphere. The mechanics are called "core accretion," and it seems to work best when the building materials are plentiful. But TOI-6894b seems to be playing by a different rulebook. It's about 53 times the weight of Earth and made partly of heavy elements, according to a paper on its discovery published in Nature Astronomy. In fact, the exoplanet is thought to have about 12 Earths'-worth of those chemicals. That's way beyond what most small young stars are thought to have in their midst. Some scientists don't want to throw the baby out with the bathwater: Though the exoplanet doesn't fit neatly into the core-accretion model, it could have formed in a similar way but with a tweak. Perhaps this world started collecting ingredients to form its core very early in its star's life, when the disk was still chock-full of raw material. Or maybe instead of growing a large core quickly to pull in more gas in a runaway process à la Jupiter-like planets, TOI-6894b could have just kept hoarding gas and heavy elements gradually over time. But even that would require a bigger original supply of dust. In a survey sample of 70 disks around small stars, only five had enough material to build a planet on the scale of TOI-6894b, according to the new paper. Another idea, called gravitational instability, suggests the disk could collapse under its own weight to create a planet directly. But the discovery team for TOI-6894 b points out that the process doesn't quite work for something the size of this exoplanet — at least according to computer simulations. Whatever the origin story, TOI-6894b is leading the ranks of other known gas giants orbiting small and faint stars that astronomers want to study. Scientists also have their eyes on LHS 3154 b, GJ 3512 b, and TZ Ari b. Small stars tend to have smaller and lighter protoplanetary disks. Credit: NASA / JPL-Caltech illustration "This discovery will be a cornerstone for understanding the extremes of giant planet formation," Bryant said. The next step for the research team is to use the James Webb Space Telescope to study the exoplanet's atmosphere, which will occur within the next year. By measuring the various materials in the planet, the researchers may be able to determine the size and structure of its core. That could answer the question of whether TOI-6894 b formed through one of the known models. They also have a hunch the exoplanet's atmosphere is rich in methane, something Webb could help confirm. TOI-6894 b is unusually cool for a gas giant, about 300 degrees Fahrenheit. Most of the gas giants known are "hot Jupiters," with temperatures between 1,340 and 3,140 degrees Fahrenheit. Such a discovery of a relatively chilly gas giant would be very rare, the researchers said. "Most stars in our galaxy are actually small stars exactly like this," said Daniel Bayliss, a coauthor from the University of Warwick in the United Kingdom. "The fact that this star hosts a giant planet has big implications for the total number of giant planets we estimate exist in our galaxy."
Irish Times
09-06-2025
- Science
- Irish Times
Likely site of new ‘gas giant' planet found by research team led by Galway scientists
The likely site of a new 'gas giant planet' up to several times the mass of Jupiter, has been discovered by an international research team led by University of Galway astronomers. Using the European Southern Observatory's Very Large Telescope (ESO's VLT) in Chile, the team has captured images around a distant young star revealing a 'new planet-forming disc' for the first time. The landmark study was led by Dr Christian Ginski from the Centre for Astronomy in the School of Natural Sciences at University of Galway. It was co-authored by four postgraduate students at the university: Chloe Lawlor, Jake Byrne, Dan McLachlan and Matthew Murphy. Published in the International Journal of Astronomy and Astrophysics, the paper's research team also included colleagues in the UK, Germany, Australia, USA, Netherlands, Italy, Chile, France and Japan. READ MORE It suggests the possible presence of a planet based on the disc's structure, which includes visible rings and spirals. Principal researcher Dr Ginski called the image 'something special', anticipating that the discovery will 'bring us one step closer to understand how planets form in general and how our solar system might have formed in the distant past'. 'While our team has now observed close to 100 possible planet-forming discs around nearby stars, this image is something special,' he said. 'One rarely finds a system with both rings and spiral arms in a configuration that almost perfectly fits the predictions of how a forming planet is supposed to shape its parent disc according to theoretical models.' The disc extends 130 astronomical units out from its 'parent star' – the equivalent to 130 times the distance between Earth and the sun. It shows a bright ring followed by a gap centred at roughly 50 astronomical units. [ Europa is our best bet of finding other life in our solar system Opens in new window ] By comparison, Neptune – the outermost planet in our solar system – has an orbital distance from the sun of 30 astronomical units. The inner part of this planet-forming system measures 40 astronomical units in radius, large enough to 'swallow all of the planets in our own solar system'. Based on their research findings, Dr Ginski and his team have secured time at the world leading James Webb Space Telescope (JWST) observatory during the upcoming observation cycle. Here, they hope to take an image of the young planet to determine whether planets exist in the disc, as suggested.
Yahoo
25-05-2025
- Science
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Scientists Find Jupiter Used to Be More Than Twice Its Current Size
You don't need us to tell you that Jupiter, which has more than twice the mass of all the other planets in the Solar System combined, is the biggest game in town (other than the Sun, at least.) But believe it or not, it may have once been even bigger. Try more than double its current size, according to new research from Caltech and the University of Michigan — boasting enough volume to fit 2,000 Earths inside it with room to spare. Over time, the bloated world cooled off, contracting to the relatively humbler size it is today. The findings, published in a new study in the journal Nature Astronomy, provide a window into the Solar System's early evolution, around 3.8 million years after the first solids formed. Jupiter, with its enormous gravitational pull — and as the first planet to form — would have played an instrumental role in determining how the orbits of the nascent planets eventually settled. "Our ultimate goal is to understand where we come from, and pinning down the early phases of planet formation is essential to solving the puzzle," co-lead author Konstantin Batygin, a professor of planetary science at Caltech, said in a statement about the work. "This brings us closer to understanding how not only Jupiter but the entire Solar System took shape." The clues to uncovering this early episode of Jupiter's past lie in two of its small moons, Amalthea and Thebe, which exhibit unusual orbits that aren't fully explained by their host's current size. To examine this discrepancy, the researchers bypassed existing planetary formation models and focused on aspects of the Jovian system that could be directly measured, including the orbital dynamics of the tiny moons and the planet's angular momentum. Their calculations revealed that, around 4.5 billion years ago, Jupiter must have had a radius up to 2.5 times greater than it is today. Likewise, its magnetic field — terrifyingly, as it's already 20,000 stronger than the Earth's — would have been a staggering 50 times more powerful. This dramatically shapes our idea of Jupiter in a critical moment in the Solar System's evolution, when the great disk of matter surrounding the Sun called the protoplanetary disk, which gave birth to the planets, evaporated. Mind-boggling as they are, these findings, the researchers say, are consistent with the prevailing core-accretion theory describing how giant planets formed. According to this theory, the giant planets began as heavy, solid cores floating on the farther and colder side of the protoplanetary disk, pulling in the lighter gas molecules surrounding them — first gradually, and then after passing a threshold of mass, much more rapidly. The exact details surrounding the planets' origins are still hotly contested. But the researchers say they've made the most precise measurements to date of primordial Jupiter's size, spin rate, and magnetic conditions, which will be indispensable to furthering our understanding of the Solar System's architecture. "What we've established here is a valuable benchmark," Batygin said. "A point from which we can more confidently reconstruct the evolution of our Solar System." More on astronomy: Astronomers Baffled by a Suspicious, Perfectly Round Sphere in Our Galaxy
