Latest news with #gasgiant
Forbes
3 days ago
- Science
- Forbes
NASA's Webb May Have Found A Planet Around The Closest Sun-Like Star
NASA has announced the probable discovery of a giant planet orbiting Alpha Centauri A, one of the closest stars to the solar system. If confirmed, it would be the nearest planet ever detected around a sun-like star. Although it's in the habitable zone of the star, it's a gas giant, so it would not support life as we know it. Astronomers using the James Webb Space Telescope found a planet while observing Alpha Centauri, a system of three stars orbiting each other — binary stars Alpha Centauri A and B, along with the red dwarf star Proxima Centauri. They're just four light-years from the solar system. Breakthrough Discovery It's been known for some time that three planets are orbiting Proxima Centauri, but planets around Alpha Centauri A — a star much like the sun — have until now proved elusive. The breakthrough came when astronomers used a coronagraph — a disk to block the bright starlight — from Alpha Centauri A, revealing a faint object around it. Around 10,000 times dimmer than the star, the planet is about twice as far from its star as Earth is from the sun. The evidence was published across two papers in The Astrophysical Journal Letters. Possible Saturn-Mass World Based on brightness and simulations, researchers believe the object could be a gas giant about the mass of Saturn — though additional observations will be needed to confirm the planet's existence. The discovery at Alpha Centauri A — the third brightest star in the night sky — could be a massive breakthrough for planetary scientists wanting to learn more about exoplanets (planets orbiting stars other than the sun). 'With this system being so close to us, any exoplanets found would offer our best opportunity to collect data on planetary systems other than our own,' said Charles Beichman, NASA's Jet Propulsion Laboratory and the NASA Exoplanet Science Institute at Caltech's IPAC astronomy center, co-first author on the new papers. 'Yet, these are incredibly challenging observations to make, even with the world's most powerful space telescope, because these stars are so bright, close, and move across the sky quickly.' Disappearing Planet? However, it's not entirely clear that this planet exists at all. First sighted in 2019 by the European Southern Observatory's Very Large Telescope, astronomers spotted it in August 2024, using the coronagraph in Webb's MIRI instrument. However, light from Alpha Centauri B made it a difficult observation. Attempts to confirm the planet's existence in February 2025 and April 2025 did not succeed. Researchers were not surprised, having modelled where the planet ought to be on its elliptical orbit. 'We found that in half of the possible orbits simulated, the planet moved too close to the star and wouldn't have been visible to Webb in both February and April 2025,' said Ph.D. student Aniket Sanghi of Caltech in Pasadena, California, the co-first author on the two papers covering the team's research. 'Its very existence in a system of two closely separated stars would challenge our understanding of how planets form, survive, and evolve in chaotic environments.' It's hoped that NASA's Nancy Grace Roman Space Telescope, set to launch as soon as 2026, could complement Webb's infrared data with visible-light observations, helping confirm the planet and figure out its size and composition. Either way, Alpha Centauri A's gas giant will be a prime target for the next generation of astronomers and telescopes. Wishing you clear skies and wide eyes.
The Independent
4 days ago
- Science
- The Independent
NASA astronomers find new signs of giant gas planet using James Webb Telescope
Astronomers have found strong evidence of a giant gas planet orbiting a star in the Alpha Centauri system, located four light-years from Earth. If confirmed, this potential planet, detected using NASA 's James Webb Space Telescope, would be the closest to Earth orbiting in the habitable zone of a sun-like star. Although the planet is a gas giant and unlikely to support life itself, scientists suggest its moons could potentially sustain life. The discovery is considered highly significant as it offers the best opportunity to gather data on planetary systems beyond our own, despite the observational challenges posed by bright stars. Confirmation of this planet would represent a new milestone for exoplanet imaging and challenge existing theories on how planets form and evolve in complex stellar environments.
WIRED
09-07-2025
- Science
- WIRED
A Giant Planet and a Small Star Are Shaking Up Conventional Cosmological Theory
Jul 9, 2025 7:00 AM A gas giant comparable in size to Saturn has been found orbiting a small red dwarf star. The discovery is making experts reconsider conventional notions of how planets form. An illustration of the giant gas planet TOI-6894b orbiting the small, dim red dwarf star TOI-6894. Illustration: University of Warwick/Mark Garlick Many of the stars in the Milky Way galaxy are small, dim red dwarfs—stars much smaller than the sun in both size and mass. TOI-6894, located far away from Earth, is one of them. Astronomers previously thought a star like this could not have large planets circulating it, because its mass is only about 20 percent of the sun, meaning its planetary system—generated from materials surrounding the star—would not have contained enough mass to form a giant body like Saturn or Jupiter. But when observing TOI-6894, an international research team detected a clear transit signal—a temporary decrease in a star's brightness caused by a planet passing across it. This newly discovered planet, named TOI-6894b, blocks 17 percent of the star's light, indicating the planet is fairly large. The signal was picked up by the Transiting Exoplanet Survey Satellite (TESS), an observation instrument launched by NASA to hunt for planets orbiting stars outside of our solar system. This makes TOI-6894 'the lowest mass star known to date to host such a planet,' said Edward Bryant, Astrophysics Prize Fellow at the University of Warwick, in a press statement. The finding appears to upend conventional theory on how planets are formed. 'This discovery will be a cornerstone for understanding the extremes of giant planet formation,' Bryant said. Astronomers at University College London and the University of Warwick, as part of a global collaboration with partners in Chile, the US, and Europe, trawled through the data of about 91,000 red dwarf stars observed by TESS before discovering the planet TOI-6894b. After that, the nature of TOI-6894b was clarified by additional observations made with other telescopes. According to these, TOI-6894b's radius is slightly larger than Saturn's, but its mass is only about half that of the ringed giant. Its density is extremely light at only 0.33 g/cm³, indicating that it is an expanding gas planet. TOI-6894 is nearly 40 percent smaller than the previous record for the smallest star with a planet of this size. This fact poses a serious contradiction to conventional theories of planet formation. The widely accepted planetary formation model, the 'core-accumulation theory,' proposes that a ring of dust and rocks—known as protoplanetary disk—forms around a star, and that materials in this disk then gather together to form the cores of planets. After starting out this way, larger gas planets then accrete gases around their cores to become gigantic. But if the mass of the star is small, the mass of its protoplanetary disk tends to be small as well. In such a scenario, the nucleus necessary for the formation of a giant gas planet will not grow. Based on this theory, it is estimated that more than 120 times more solid matter than that of the Earth would be required to form TOI-6894b. However, the observed disk surrounding the star TOI-6894 contains only 58 times the mass of the Earth at most. This raises the possibility of an alternative planet-formation mechanism existing. One suggestion by Bryant and the team is that planets could form by gradual gas accumulation, without the initial formation of a massive core. 'Alternatively, it could have formed because of a gravitationally unstable disc,' Bryant says. 'In some cases, the disc surrounding the star will become unstable due to the gravitational force it exerts on itself. These discs can then fragment, with the gas and dust collapsing to form a planet.' However, the press statement goes on to explain that neither of these theories can could completely explain the formation of TOI-6894b, based on the data gathered. For now the planet's origin remains a mystery. Analyzing the atmosphere of the newly discovered exoplanet might yield answers; it is possible that chemical traces of its formation process remain. Observations of TOI-6894b by the James Webb Space Telescope over the next 12 months are expected to reveal details about its interior structure and atmospheric composition, which will have a major say on whether current theories about planet formation are supported or new ones are needed. The discovery may force us to rethink our unified model of planet formation, says Andrés Jordán of the Millennium Astrophysics Institute at Adolfo Ibáñez University in Chile. Years of steady observations are pushing the limits of theory, and it may even be time to fundamentally rethink our estimates of the total number of giant planets in the galaxy. This story originally appeared on WIRED Japan and has been translated from Japanese.
Yahoo
04-07-2025
- Science
- Yahoo
NASA exoplanet-hunting spacecraft and citizen scientists discover a cool new alien world
When you buy through links on our articles, Future and its syndication partners may earn a commission. A new gas giant world discovered by citizen scientists using data from NASA's exoplanet-hunting spacecraft TESS is cool, literally and figuratively. The extrasolar planet, or "exoplanet," designated TOI-4465 b is located around 400 light-years from Earth. It has a mass of around six times that of Jupiter, and it's around 1.25 times as wide as the solar system's largest planet. What is really exciting about TOI-4465 b, however, is the fact that it circles its star at a distance of around 0.4 times the distance between Earth and the sun in a flattened or "elliptical" orbit. One year for this planet takes around 102 Earth days to complete. Its distance from its star gives it an estimated temperature of between 200 and 400 degrees Fahrenheit (93 to 204 degrees Celsius). This makes TOI-4465 b a rare case of a giant planet that is large, massive, dense, and relatively cool, existing in an underexplored region around its star in terms of what we know about planet size and mass. Planets like TOI-4465 b are cool prospects for exoplanet scientists to study because they bridge the gap between "hot Jupiters," scorching planets that orbit so close to their stars that their years last a matter of hours, and frigid ice giant worlds like the solar system's own Neptune and Uranus. Unfortunately, we don't know of many such worlds because they are difficult to detect. "This discovery is important because long-period exoplanets, defined as having orbital periods longer than 100 days, are difficult to detect and confirm due to limited observational opportunities and resources," team leader and University of Mexico researcher Zahra Essack said in a statement. "As a result, they are underrepresented in our current catalog of exoplanets. "Studying these long-period planets gives us insights into how planetary systems form and evolve under more moderate conditions.' The rarity of such exoplanets makes TOI-4465 b a prime target for future investigation with the James Webb Space Telescope (JWST). But just how did the JWST's sibling, NASA spacecraft, TESS (Transiting Exoplanet Survey Satellite), detect such an elusive planet to begin with? TESS detects planets when they "transit" the face of their parent star, meaning they cross between their star and Earth. This causes a tiny dip in the light received from that star. TOI-4465 b was spotted by TESS during a single fleeting transit event. That meant, in order to confirm this planet, the team needed to observe at least one more transit event. Something easier said than done due to some frustrating complications. "The observational windows are extremely limited," Essack explained. "Each transit lasts about 12 hours, but it is incredibly rare to get 12 full hours of dark, clear skies in one location. The difficulty of observing the transit is compounded by weather, telescope availability, and the need for continuous coverage.' To combat these issues, the team turned to the Unistellar Citizen Science Network, calling upon 24 of its citizen scientists across 10 countries. These amateur astronomers used their personal telescopes to observe TOI-4465 b's host star. Combining this data with observations from several professional observatories resulted in the discovery of that elusive second transit, thus confirming TOI-4465 b. "The discovery and confirmation of TOI-4465 b not only expands our knowledge of planets in the far reaches of other star systems but also shows how passionate astronomy enthusiasts can play a direct role in frontier scientific research," Essack said. Related Stories: —The James Webb Space Telescope has discovered its 1st exoplanet and snapped its picture (image) —Astronomers discover origins of mysterious double hot Jupiter exoplanets: 'It is a dance of sorts' —Strange multi-planet system proves not all hot Jupiter exoplanets are lonely giants The discovery of this planet wouldn't have been possible without international collaborations and several initiatives, including the TESS Follow-up Observing Program Sub Group 1 (TFOP SG1), the Unistellar Citizen Science Network, and the TESS Single Transit Planet Candidate (TSTPC) Working Group. "What makes this collaboration effective is the infrastructure behind it," Essack added. "It is a great example of the power of citizen science, teamwork, and the importance of global collaboration in astronomy." The team's research was published on Wednesday (June 25) in The Astrophysical Journal.
Yahoo
01-07-2025
- Science
- Yahoo
Jupiter news, features and articles
When you buy through links on our articles, Future and its syndication partners may earn a commission. Jupiter is so large that it's known as the king of planets. At Live Science, we bask in its gassy glory by publishing facts and findings about the giant, including coverage of how Jupiter's unearthly beauty was revealed in a gorgeous true-color image, how scientists found remains of cannibalized baby planets in Jupiter's cloud-covered belly and how the mystery of Jupiter's powerful X-ray auroras was finally solved. So, if you want to learn more about our solar system's largest planet, check out the latest Jupiter news, features and articles by our expert writers and editors. —Jupiter: Facts about the biggest planet in our solar system —Could a spaceship fly through a gas giant like Jupiter?
