Webb wows with incredible detail in actively forming star system, Lynds 483 (L483)
High-resolution near-infrared light captured by the NASA/ESA/CSA James Webb Space Telescope shows extraordinary new detail and structure in Lynds 483 (L483). Two actively forming stars are responsible for the shimmering ejections of gas and dust that gleam in orange, blue, and purple in this representative colour image.
Credit: NASA, ESA, CSA, STScI
Over tens of thousands of years, the central protostars [1] have periodically ejected some of the gas and dust, spewing it out as tight, fast jets and slightly slower outflows that “trip” across space. When more recent ejections hit older ones, the material can crumple and twirl based on the densities of what is colliding. Over time, chemical reactions within these ejections and the surrounding cloud have produced a range of molecules, like carbon monoxide, methanol, and several other organic compounds.
Dust-encased stars
The two protostars responsible for this scene are at the centre of the hourglass shape, in an opaque horizontal disk of cold gas and dust that fits within a single pixel. Much farther out, above and below the flattened disk where dust is thinner, the bright light from the stars shines through the gas and dust, forming large semi-transparent orange cones.
It’s equally important to notice where the stars’ light is blocked — look for the exceptionally dark, wide V-shapes offset by 90 degrees from the orange cones. These areas may look like there is no material, but it’s actually where the surrounding dust is the densest, and little starlight penetrates it. If you look carefully at these areas, Webb’s sensitive NIRCam (Near-Infrared Camera) has picked up distant stars as muted orange pinpoints behind this dust. Where the view is free of obscuring dust, stars shine brightly in white and blue.
Unraveling the stars’ ejections
Some of the stars’ jets and outflows have wound up twisted or warped. To find examples, look toward the top right edge where there’s a prominent orange arc. This is a shock front, where the stars’ ejections were slowed by existing, denser material.
Now, look a little lower, where orange meets pink. Here, the material looks like a tangled mess. These are new, incredibly fine details Webb has revealed, and will require detailed study to explain.
Turn to the lower half. Here, the gas and dust appear thicker. Zoom in to find tiny light purple pillars. They point toward the central stars’ nonstop winds, and formed because the material within them is dense enough that it hasn’t yet been blown away. L483 is too large to fit in a single Webb snapshot, and this image was taken to fully capture the upper section and outflows, which is why the lower section is only partially shown.
All the symmetries and asymmetries in these clouds may eventually be explained as researchers reconstruct the history of the stars’ ejections, in part by updating models to produce the same effects. Astronomers will also eventually calculate how much material the stars have expelled, which molecules were created when material smashed together, and how dense each area is.
Millions of years from now, when the stars are finished forming, they may each be about the mass of our Sun. Their outflows will have cleared the area — sweeping away these semi-transparent ejections. All that may remain is a tiny disk of gas and dust where planets may eventually form.
L483 is named for American astronomer Beverly T. Lynds, who published extensive catalogues of “dark” and “bright” nebulae in the early 1960s. She did this by carefully examining photographic plates (which preceded film) of the first Palomar Observatory Sky Survey, accurately recording each object’s coordinates and characteristics. These catalogues provided astronomers with detailed maps of dense dust clouds where stars form — critical resources for the astronomical community decades before the first digital files became available and access to the internet was widespread.
The scale bar is labelled in light-years, which is the distance that light travels in one Earth-year. (It takes 0.1 years for light to travel a distance equal to the length of the scale bar.) One light-year is equal to 9.46 trillion kilometres. This image shows invisible near-infrared wavelengths of light that have been translated into visible-light colours. The colour key shows which NIRCam filters were used when collecting the light. The colour of each filter name is the visible light colour used to represent the infrared light that passes through that filter.
Credit: NASA, ESA, CSA, STScI
Notes
[1] A protostar is a collection of interstellar gas and dust whose gravitational pull is causing it to collapse on itself and form a star.
Press release from ESA Webb.
