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By NASA
Illustration of the main asteroid belt, orbiting the Sun between Mars and JupiterNASA NASA’s powerful James Webb Space Telescope includes asteroids on its list of objects studied and secrets revealed.
A team led by researchers at the Massachusetts Institute of Technology (MIT) in Cambridge repurposed Webb’s observations of a distant star to reveal a population of small asteroids — smaller than astronomers had ever detected orbiting the Sun in the main asteroid belt between Mars and Jupiter.
The 138 new asteroids range from the size of a bus to the size of a stadium — a size range in the main belt that has not been observable with ground-based telescopes. Knowing how many main belt asteroids are in different size ranges can tell us something about how asteroids have been changed over time by collisions. That process is related to how some of them have escaped the main belt over the solar system’s history, and even how meteorites end up on Earth.
“We now understand more about how small objects in the asteroid belt are formed and how many there could be,” said Tom Greene, an astrophysicist at NASA’s Ames Research Center in California’s Silicon Valley and co-author on the paper presenting the results. “Asteroids this size likely formed from collisions between larger ones in the main belt and are likely to drift towards the vicinity of Earth and the Sun.”
Insights from this research could inform the work of the Asteroid Threat Assessment Project at Ames. ATAP works across disciplines to support NASA’s Planetary Defense Coordination Office by studying what would happen in the case of an Earth impact and modeling the associated risks.
“It’s exciting that Webb’s capabilities can be used to glean insights into asteroids,” said Jessie Dotson, an astrophysicist at Ames and member of ATAP. “Understanding the sizes, numbers, and evolutionary history of smaller main belt asteroids provides important background about the near-Earth asteroids we study for planetary defense.”
Illustration of the James Webb Space TelescopeNASA The team that made the asteroid detections, led by research scientist Artem Burdanov and professor of planetary science Julien de Wit, both of MIT, developed a method to analyze existing Webb images for the presence of asteroids that may have been inadvertently “caught on film” as they passed in front of the telescope. Using the new image processing technique, they studied more than 10,000 images of the star TRAPPIST-1, originally taken to search for atmospheres around planets orbiting the star, in the search for life beyond Earth.
Asteroids shine more brightly in infrared light, the wavelength Webb is tuned to detect, than in visible light, helping reveal the population of main belt asteroids that had gone unnoticed until now. NASA will also take advantage of that infrared glow with an upcoming mission, the Near-Earth Object (NEO) Surveyor. NEO Surveyor is the first space telescope specifically designed to hunt for near-Earth asteroids and comets that may be potential hazards to Earth.
The paper presenting this research, “Detections of decameter main-belt asteroids with JWST,” was published Dec. 9 in Nature.
The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).
For news media:
Members of the news media interested in covering this topic should reach out to the NASA Ames newsroom.
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By NASA
ESA/Webb, NASA & CSA, P. Zeidler This new image of star cluster NGC 602, released on Dec. 17, 2024, combines data from NASA’s Chandra X-ray Observatory with a previously released image from the agency’s James Webb Space Telescope. Webb data provide the ring-like outline of the “wreath,” while X-rays from Chandra (red) show young, massive stars that are illuminating the wreath, sending high-energy light into interstellar space.
NGC 602 lies on the outskirts of the Small Magellanic Cloud, which is one of the closest galaxies to the Milky Way, about 200,000 light-years from Earth.
See another new, festive image: the “Christmas tree cluster.”
Image credit: X-ray: NASA/CXC; Infrared: ESA/Webb, NASA & CSA, P. Zeilder, E.Sabbi, A. Nota, M. Zamani; Image Processing: NASA/CXC/SAO/L. Frattare and K. Arcand
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By NASA
Webb Webb News Latest News Latest Images Blog (offsite) Awards X (offsite – login reqd) Instagram (offsite – login reqd) Facebook (offsite- login reqd) Youtube (offsite) Overview About Who is James Webb? Fact Sheet Impacts+Benefits FAQ Science Overview and Goals Early Universe Galaxies Over Time Star Lifecycle Other Worlds Observatory Overview Launch Orbit Mirrors Sunshield Instrument: NIRCam Instrument: MIRI Instrument: NIRSpec Instrument: FGS/NIRISS Optical Telescope Element Backplane Spacecraft Bus Instrument Module Multimedia About Webb Images Images Videos What is Webb Observing? 3d Webb in 3d Solar System Podcasts Webb Image Sonifications Team International Team People Of Webb More For the Media For Scientists For Educators For Fun/Learning 7 Min Read NASA’s Webb Finds Planet-Forming Disks Lived Longer in Early Universe
This is a James Webb Space Telescope image of NGC 346, a massive star cluster in the Small Magellanic Cloud, a dwarf galaxy that is one of the Milky Way’s nearest neighbors. Credits:
NASA, ESA, CSA, STScI, Olivia C. Jones (UK ATC), Guido De Marchi (ESTEC), Margaret Meixner (USRA) NASA’s James Webb Space Telescope just solved a conundrum by proving a controversial finding made with the agency’s Hubble Space Telescope more than 20 years ago.
In 2003, Hubble provided evidence of a massive planet around a very old star, almost as old as the universe. Such stars possess only small amounts of heavier elements that are the building blocks of planets. This implied that some planet formation happened when our universe was very young, and those planets had time to form and grow big inside their primordial disks, even bigger than Jupiter. But how? This was puzzling.
To answer this question, researchers used Webb to study stars in a nearby galaxy that, much like the early universe, lacks large amounts of heavy elements. They found that not only do some stars there have planet-forming disks, but that those disks are longer-lived than those seen around young stars in our Milky Way galaxy.
“With Webb, we have a really strong confirmation of what we saw with Hubble, and we must rethink how we model planet formation and early evolution in the young universe,” said study leader Guido De Marchi of the European Space Research and Technology Centre in Noordwijk, Netherlands.
Image A: Protoplanetary Disks in NGC 346 (NIRCam Image)
This is a James Webb Space Telescope image of NGC 346, a massive star cluster in the Small Magellanic Cloud, a dwarf galaxy that is one of the Milky Way’s nearest neighbors. With its relative lack of elements heavier than hydrogen and helium, the NGC 346 cluster serves as a nearby proxy for studying stellar environments with similar conditions in the early, distant universe. Ten, small, yellow circles overlaid on the image indicate the positions of the ten stars surveyed in this study. NASA, ESA, CSA, STScI, Olivia C. Jones (UK ATC), Guido De Marchi (ESTEC), Margaret Meixner (USRA) A Different Environment in Early Times
In the early universe, stars formed from mostly hydrogen and helium, and very few heavier elements such as carbon and iron, which came later through supernova explosions.
“Current models predict that with so few heavier elements, the disks around stars have a short lifetime, so short in fact that planets cannot grow big,” said the Webb study’s co-investigator Elena Sabbi, chief scientist for Gemini Observatory at the National Science Foundation’s NOIRLab in Tucson. “But Hubble did see those planets, so what if the models were not correct and disks could live longer?”
To test this idea, scientists trained Webb on the Small Magellanic Cloud, a dwarf galaxy that is one of the Milky Way’s nearest neighbors. In particular, they examined the massive, star-forming cluster NGC 346, which also has a relative lack of heavier elements. The cluster served as a nearby proxy for studying stellar environments with similar conditions in the early, distant universe.
Hubble observations of NGC 346 from the mid 2000s revealed many stars about 20 to 30 million years old that seemed to still have planet-forming disks around them. This went against the conventional belief that such disks would dissipate after 2 or 3 million years.
“The Hubble findings were controversial, going against not only empirical evidence in our galaxy but also against the current models,” said De Marchi. “This was intriguing, but without a way to obtain spectra of those stars, we could not really establish whether we were witnessing genuine accretion and the presence of disks, or just some artificial effects.”
Now, thanks to Webb’s sensitivity and resolution, scientists have the first-ever spectra of forming, Sun-like stars and their immediate environments in a nearby galaxy.
“We see that these stars are indeed surrounded by disks and are still in the process of gobbling material, even at the relatively old age of 20 or 30 million years,” said De Marchi. “This also implies that planets have more time to form and grow around these stars than in nearby star-forming regions in our own galaxy.”
Image B: Protoplanetary Disks in NGC 346 Spectra (NIRSpec)
This graph shows, on the bottom left in yellow, a spectrum of one of the 10 target stars in this study (as well as accompanying light from the immediate background environment). Spectral fingerprints of hot atomic helium, cold molecular hydrogen, and hot atomic hydrogen are highlighted. On the top left in magenta is a spectrum slightly offset from the star that includes only light from the background environment. This second spectrum lacks a spectral line of cold molecular hydrogen.
On the right is the comparison of the top and bottom lines. This comparison shows a large peak in the cold molecular hydrogen coming from the star but not its nebular environment. Also, atomic hydrogen shows a larger peak from the star. This indicates the presence of a protoplanetary disk immediately surrounding the star. The data was taken with the microshutter array on the James Webb Space Telescope’s NIRSpec (Near-Infrared Spectrometer) instrument. Illustration: NASA, ESA, CSA, Joseph Olmsted (STScI) A New Way of Thinking
This finding refutes previous theoretical predictions that when there are very few heavier elements in the gas around the disk, the star would very quickly blow away the disk. So the disk’s life would be very short, even less than a million years. But if a disk doesn’t stay around the star long enough for the dust grains to stick together and pebbles to form and become the core of a planet, how can planets form?
The researchers explained that there could be two distinct mechanisms, or even a combination, for planet-forming disks to persist in environments scarce in heavier elements.
First, to be able to blow away the disk, the star applies radiation pressure. For this pressure to be effective, elements heavier than hydrogen and helium would have to reside in the gas. But the massive star cluster NGC 346 only has about ten percent of the heavier elements that are present in the chemical composition of our Sun. Perhaps it simply takes longer for a star in this cluster to disperse its disk.
The second possibility is that, for a Sun-like star to form when there are few heavier elements, it would have to start from a larger cloud of gas. A bigger gas cloud will produce a bigger disk. So there is more mass in the disk and therefore it would take longer to blow the disk away, even if the radiation pressure were working in the same way.
“With more matter around the stars, the accretion lasts for a longer time,” said Sabbi. “The disks take ten times longer to disappear. This has implications for how you form a planet, and the type of system architecture that you can have in these different environments. This is so exciting.”
The science team’s paper appears in the Dec. 16 issue of The Astrophysical Journal.
Image C: NGC 346: Hubble and Webb Observations
Image Before/After The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).
The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt manages the telescope and mission operations. Lockheed Martin Space, based in Denver also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.
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Media Contacts
Laura Betz – laura.e.betz@nasa.gov
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Ann Jenkins – jenkins@stsci.edu, Christine Pulliam – cpulliam@stsci.edu
Space Telescope Science Institute, Baltimore, Md.
Related Information
Past releases on NGC 346: Webb NIRCam image and MIRI image
Article: Highlighting other Webb Star Formation Discoveries
Simulation Video: Planetary Systems and Origins of Life
Animation Video: Exploring star and planet formation (English), and in Spanish
More Images of NGC 346 on AstroPix
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Astrophysics Galaxies Galaxies, Stars, & Black Holes Goddard Space Flight Center James Webb Space Telescope (JWST) Science & Research Stars The Universe View the full article
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By European Space Agency
For the first time, the NASA/ESA/CSA James Webb Space Telescope has detected and ‘weighed’ a galaxy, in the early Universe, that has a mass that is similar to what our Milky Way galaxy’s mass might have been at the same stage of development. Found at around 600 million years after the Big Bang, this lightweight galaxy, nicknamed the Firefly Sparkle, is gleaming with star clusters – 10 in total – that researchers examined in great detail. Other galaxies Webb has detected at this period in the history of the Universe are significantly more massive.
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By NASA
At Goddard Space Flight Center, the GSFC Data Science Group has completed the testing for their SatVision Top-of-Atmosphere (TOA) Foundation Model, a geospatial foundation model for coarse-resolution all-sky remote sensing imagery. The team, comprised of Mark Carroll, Caleb Spradlin, Jordan Caraballo-Vega, Jian Li, Jie Gong, and Paul Montesano, has now released their model for wide application in science investigations.
Foundation models can transform the landscape of remote sensing (RS) data analysis by enabling the pre-training of large computer-vision models on vast amounts of remote sensing data. These models can be fine-tuned with small amounts of labeled training and applied to various mapping and monitoring applications. Because most existing foundation models are trained solely on cloud-free satellite imagery, they are limited to applications of land surface or require atmospheric corrections. SatVision-TOA is trained on all-sky conditions which enables applications involving atmospheric variables (e.g., cloud or aerosol).
SatVision TOA is a 3 billion parameter model trained on 100 million images from Moderate Resolution Imaging Spectroradiometer (MODIS). This is, to our knowledge, the largest foundation model trained solely on satellite remote sensing imagery. By including “all-sky” conditions during pre-training, the team incorporated a range of cloud conditions often excluded in traditional modeling. This enables 3D cloud reconstruction and cloud modeling in support of Earth and climate science, offering significant enhancement for large-scale earth observation workflows.
With an adaptable and scalable model design, SatVision-TOA can unify diverse Earth observation datasets and reduce dependency on task-specific models. SatVision-TOA leverages one of the largest public datasets to capture global contexts and robust features. The model could have broad applications for investigating spectrometer data, including MODIS, VIIRS, and GOES-ABI. The team believes this will enable transformative advancements in atmospheric science, cloud structure analysis, and Earth system modeling.
The model architecture and model weights are available on GitHub and Hugging Face, respectively. For more information, including a detailed user guide, see the associated white paper: SatVision-TOA: A Geospatial Foundation Model for Coarse-Resolution All-Sky Remote Sensing Imagery.
Examples of image reconstruction by SatVision-TOA. Left: MOD021KM v6.1 cropped image chip using MODIS bands [1, 3, 2]. Middle: The same images with randomly applied 8×8 mask patches, masking 60% of the original image. Right: The reconstructed images produced by the model, along with their respective Structural Similarity Index Measure (SSIM) scores. These examples illustrate the model’s ability to preserve structural detail and reconstruct heterogeneous features, such as cloud textures and land-cover transitions, with high fidelity.NASAView the full article
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