JWST images young disks

Planet-forming disks are rings of gas and dust around newborn stars, like a flat cloud that can slowly clump into worlds. New James Webb Space Telescope images show two of them edge-on, turning that process into bright hourglass shapes above and below dark central lanes. (esa.int) The two systems are Tau 042021 in Taurus and Oph 163131 in Ophiuchus, also cataloged as 2MASS J04202144+2813491 and 2MASS J16313124-2426281. The European Space Agency said Tau 042021 is about 450 light-years away and Oph 163131 is about 480 light-years away. (esawebb.org) Astronomers see both disks nearly edge-on, so the star in the middle is mostly blocked and the dust above and below the disk lights up in reflected starlight. That viewing angle makes the systems useful because it separates the dark disk itself from the glowing material lofted over it. (esawebb.org) In a protoplanetary disk, leftover material from star formation collides and sticks together into larger bodies called planetesimals, which can later become planets. Gas that does not end up in planets is then blown away by the young star’s radiation over tens of millions of years. (esawebb.org) The new images were built from Webb’s Near-Infrared Camera and Mid-Infrared Instrument, which observe heat and reflected light at wavelengths from about 2 to 21 microns. The European Space Agency said that broad infrared coverage lets researchers trace dust grains of different sizes across the disks. (esawebb.org; arxiv.org) Color in the images marks different ingredients and grain sizes, including hydrogen, carbon monoxide and complex carbon-bearing molecules called polycyclic aromatic hydrocarbons. The Oph 163131 composite also includes data from the Atacama Large Millimeter/submillimeter Array, while both images include visible-light data from the Hubble Space Telescope. (esawebb.org) Tau 042021 has already been the subject of a Webb study published in The Astronomical Journal in 2024. That paper reported a disk about 1,000 astronomical units in radius around a young star with about 0.4 times the Sun’s mass, and found that grains up to at least 10 microns appear mixed high into the disk’s outer layers. (ntrs.nasa.gov; arxiv.org) Oph 163131 had been studied before with the Atacama Large Millimeter/submillimeter Array and was described in earlier work as an edge-on disk around a weak-line T Tauri star with an inclination of about 84 degrees. A later Webb paper posted in 2024 said Oph 163131 shows a strong change in appearance from near-infrared to mid-infrared wavelengths, unlike some other edge-on disks. (webdisks.jpl.nasa.gov; arxiv.org) NASA has said Webb was built to study the chemistry and structure of planet-forming disks with higher infrared sensitivity and resolution than earlier observatories. These two pictures do not show finished planets, but they do show where dust and gas are arranged while planetary systems are still being assembled. (science.nasa.gov; esawebb.org)