JWST shows a new side of planet formation

All across the Milky Way, new stars continuously form.

This region of space shows a portion of the plane of the Milky Way, with three extended star-forming regions all side-by-side next to one another. The Omega Nebula (left), the Eagle Nebula (center), and Sharpless 2-54 (right), compose just a small fraction of a vast complex of gas and dust found all through the galactic plane that continuously lead to the formation of newborn stars.

Large concentrations of mass gather, triggering gas cloud collapse.

Near Orion’s Belt, the reflection nebula known as the Flame Nebula (left) as well as the star-forming emission nebula known as IC 434 (in red) are joined by a series of dark molecular clouds in the foreground that create spectacular silhouettes known as dark nebulae. The Horsehead Nebula (at center) is arguably the most famous dark nebula of them all.

At high temperatures and densities, nuclear fusion ignites.

This image shows the Orion Molecular Clouds, the target of the VANDAM survey. Yellow dots are the locations of the observed protostars on a blue background image made by Herschel. Side panels show nine young protostars imaged by ALMA (blue) and the VLA (orange). Protoplanetary disks not only are rich in organic molecules, but contain species that are not often seen in typical interstellar dust clouds. For several million years after fusion in the star’s core ignites, circumstellar gas-rich material persists.

These newborn stars, with protoplanetary disks, give rise to stellar and planetary systems.

This view from the James Webb Space Telescope (JWST) of the protoplanetary disk, or proplyd, Orion 294-606 showcases not only how magnificent JWST is at imaging objects like this, but also how distant stellar systems truly are from one another, even within the star-forming regions where they’re created. This newly-forming object is due to a collapsing gas cloud and will someday become a star, but is not yet one. Stars only need a small fraction of the heavy elements that the Sun possesses in order to form planets.

The closest star-forming region to Earth is obscure: the Taurus molecular cloud.

This far-infrared view of a portion of the Taurus Molecular Cloud comes from the ESA’s (now-defunct) Herschel space observatory: the only far-infrared space telescope ever of the 21st century. Within this molecular cloud complex lie the youngest and closest newly-forming stars known with respect to our own Solar System.

Just 460 light-years away, it contains a dark cloud shrouding protostar L1527.

This animation switches between an optical view of the dark molecular cloud that houses protostar L1527 (red circle), and infrared data from the WISE mission that showcases the protoplanetary system and its outflows directly.

Imaged more than a decade ago in infrared light, protostellar features shine through.

This graphic shows the protostar at the heart of dark cloud L1527 as well as the protoplanetary disk imaged inside of it. The coarse features are provided by NASA’s Spitzer, the predecessor to JWST, while the fine features of the disk are provided by the ground-based 8-meter Gemini telescope.

Observations indicate the presence of a disk containing complex molecules.

The protostar embedded in dark cloud L1527 is known as IRAS 04368+2557, and has a protostellar disk about 180 A.U. wide that is expected to form a planetary system. Spitzer observations, highlighted here, showcase molecules like cyclic-C3H2 and sulfur monoxide.

At radio wavelengths, clumpy features show rich structures forming inside.

These radio observations of the protoplanetary disk at the center of dark cloud L1527 come from ALMA and the VLA. They showcase the dust distribution in the infant disk, and provide evidence for clumps within the disk, located just ~15 A.U. from the central clump. For a system that’s only 100,000 years old, a non-uniform disk is exceedingly rare.

However, a remarkable set of JWST observations reveal new details within this object.

This view of protostar L1527 shows the NIRCam and MIRI views from JWST rotated and stretched in order to transition between them. Although both views showcase important features of the outflows from this object, near-infrared and mid-infrared wavelengths are sensitive to different features: gas, dust, molecules, and more.

NIRCam imagery, in the near-infrared, showcases blown-out cavities perpendicular to the disk.

The glowing bi-directional features shown here are due to ejections from the central protostar within the dark molecular cloud L1527. The orange regions are heavily shrouded in dust, while the blue regions are more dust-free. Large-scale molecular filaments, made largely of hydrogen that have been recently shocked, are also apparent here.

Gaseous knots and uneven ejecta indicate sporadic activity from the central protostar.

The bubble-like shapes shown in the upper central region of the hourglass, as revealed here by JWST’s NIRCam, are due to what are sometimes called stellar burps, as these sporadic, uneven ejections create energized features that interact with the pre-existing surrounding matter.

The edge-on disk blocks light effectively, perpendicular to both lobes.

The central region of protostar L1527, as imaged by JWST’s NIRCam, shows the edge-on protoplanetary disk and ejecta perpendicular to it. Although the disk appears to be invisible farther to the left and right of the image here, the background objects are obscured and reddened, indicating that the light-blocking material extends much farther than the illuminated regions.

At longer wavelengths, MIRI’s mid-infrared views showcase different features.

This full-scale image of MIRI’s view of protostar L1527 shows a protostellar system that’s only about 100,000 years old, still surrounded by the molecular cloud that birthed it. The outflows, which collide with the surrounding molecular cloud, give rise to the hourglass shape and the knotty features seen here.

Extended blue filaments reveal complex carbon-ringed molecules: polycyclic aromatic hydrocarbons.

The wispy, blue-colored feature as seen by JWST’s MIRI showcase outflowing carbon-containing molecules known as polycyclic aromatic hydrocarbons. Whereas the white features near the center show off a combination of ionized and excited atomic and molecular features, the diffuse blue filaments show off these primitive organic compounds.

The red, central region is energy-rich, with thick layers of gas and dust.

Although the red light at the center of L1527, as it appears in MIRI imagery, indicated an energized, thick layer of dust and gas, the spiky features emerging from the center are simply diffraction spikes due to JWST’s mirror shape and mirror-obscuring struts.

However, the “spikes” are simply artifacts of JWST’s architecture.

Mainly due to the shape of JWST’s primary mirror system (right) and on account of the struts that hold the secondary mirror in place (left), JWST’s observations of bright, point-like sources do not yield single points, but rather an eight-spike pattern known, perhaps not so poetically, as the nightmare snowflake. This pattern shows up ubiquitously in NIRCam and MIRI imagery.

NIRCam’s and MIRI’s differences highlight wavelength-dependent features.

This side-by-side view of JWST’s NIRCam (left) and MIRI (right) views of dark cloud L1527 shows not darkness, but rather illuminated features that highlight gas, dust, shocks, and more. Although MIRI’s views are much lower resolution, the views can be synthesized together with the proper application of stretching and rotating the images.

Inside the disk, planet formation is still ongoing.

Whereas the NIRCam views of L1527 show off bow shocks, filaments, and reflected dust features, MIRI highlights the thickest regions of gas and dust. As a result, the MIRI image appears much smaller, as NIRCam is sensitive to a much wider range of signals at much lower luminosities.

Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words.