The James Webb Space Telescope's (JWST) picture of the month shows Tau 042021 (left) and Oph 163131 (right), two protoplanetary disks located about 450 and 480 light-years from Earth in the constellations Taurus and Ophiuchus (respectively). These disks are composed of material left over from the formation of new stars, which coalesce into planetesimals that can eventually form a planetary system. The gas that remains is blown away by solar radiation while smaller objects (asteroids and iceteroids) settle into belts or follow the orbit of planets.
These two objects were imaged edge-on using Webb's Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI). This causes most of the light from the new star to become obscured by the disk, while dust that has risen above and below is lit by its reflected light. The broad infrared coverage of Webb's instruments allows astronomers to track dust grains of different sizes across the disc. Images like these are not only beautiful but also essential for determining the distribution of gas and dust in the disks and their respective compositions.
The red, orange, and green indicate different molecules, hydrogen (H2), carbon monoxide (CO), and polycyclic aromatic hydrocarbons (PAHs), as well as the various sizes of dust grains in the disc. Both images also feature visible-light data from the Hubble Space Telescope, primarily from the central star and reflected by fine dust grains. The image of Oph 163131 also includes radio data from the Atacama Large Millimeter/submillimeter Array (ALMA), which reveals larger dust grains concentrated in the disk's central plane.
In addition, the ALMA data for Oph 163131 shows a gap in the inner disc, which may be evidence of a planet forming and clearing out the dust around it. The images were obtained as part of Webb's Cycle 1 General Observation (GO) program #2562, "Dust Settling and Grain Evolution in Edge-on Protoplanetary Disks". By studying such disks, astronomers hope to learn more about the formation and evolution of our Solar System and the many exoplanets that have been discovered (6,153 to date, and counting).
Further Reading: ESA
