New JWST view showcases our cosmic isolation

Within our own Milky Way, new stars are currently being formed.

This Hubble composite of the Orion Nebula includes objects Messier 42 and Messier 43, spans about 24 light-years across, and shines with both emitted and reflected light from thousands of new stars. The enormously bright “pink” features are a combination of the white light emitted from stars and reflected off of the neutral matter, with the red transition of hydrogen atoms, the Balmer-alpha transition, superimposed atop that white light.

The closest major star-forming region is the Orion Nebula, visible to naked human eyes.

Illuminated by the combined processes of reflected starlight, emissions from transitions in hydrogen atoms, and the absorption of background light from neutral atoms, the great Orion Molecular Cloud Complex spans hundreds of light years, a significant fraction of which is off-screen to the left of the main constellation of Orion, shown here. The Orion Nebula is the relatively small, bright region located below the belt of Orion, showcased at the center of the image, here.

Part of a great molecular cloud complex hundreds of light-years across, the Orion Nebula is comparatively concentrated.

This infrared view of the Orion Nebula showcases a great number of stars normally hidden by the neutral atoms of the nebula itself. In infrared light, the neutral matter is largely transparent, revealing the normally obscured stars and proto-stars inside. The brightest regions correspond to the locations of the newest star clusters, including the great Trapezium cluster at the center.

With thousands of solar masses of material concentrated across just 24 light-years, over 2800 new stars already exist inside.

This composite visible light (dusty) and infrared (star-rich) view of the Trapezium cluster reveals the matter within the Orion Nebula as well as the brilliant stars inside. The Trapezium cluster is the largest, densest, brightest collection of stars inside the nearby Orion Nebula.

The densest such region is known as the Trapezium cluster: rich in young, massive stars.

This Hubble view of the Orion Nebula has a variety of proplyds, or protoplanetary disks, superimposed atop it. All told, some 42 proplyds were identified within the Orion Nebula during the Hubble era. Now, in the JWST era, over 130 such proplyds are known in the Orion Nebula alone.

Previously, NASA’s Hubble scanned through the Orion Nebula, searching for evolving proto-stars.

This selection of 30 proplyds from within the Orion Nebula, as identified by the Hubble Space Telescope, showcases the extreme variety of shapes and shadowy silhouettes found within this environment. Shadows and streams are shown in a few of them: a result of bright, nearby stars. However, most of the proplyds seen are revealed in relative isolation, with the dusty disk providing a dark foreground absorptive effect against the backdrop of reflected starlight off of the dusty Orion Nebula’s interstellar medium.

150 proplyds — newborn systems with protoplanetary disks — were discovered.

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.

Within each such disk, new planetary systems are arising.

A sample of 20 protoplanetary disks around young, infant stars, as measured by the Disk Substructures at High Angular Resolution Project: DSHARP. Observations such as these taught us that protoplanetary disks form primarily in a single plane and tend to support the core accretion scenario of planet formation. The disk structures are seen in both infrared and millimeter/submillimeter wavelengths. We have recently learned that gaps begin to form in protoplanetary disks after ~0.5-2 million years, with younger disks displaying no such substructure. These disks tend to disappear and give way to debris disk systems after around ~10 million years. Debris disks can then persist for hundreds of millions of years.

Infrared and radio observatories reveal planetary presences carved into these disks.

A composite radio/visible image of the protoplanetary disk and jet around HD 163296. The protoplanetary disk and features are revealed by ALMA in the radio, while the blue optical features are revealed by the MUSE instrument aboard the ESO’s Very Large Telescope. The gaps between the rings are likely locations of newly forming planets.

Proplyds close to massive stars always experience ablation from ultraviolet radiation.

Several views of details of protoplanetary disks are available from different observatories. ALMA (left), in submillimetre wavelengths, reveals gaps in the disk where young protoplanets are forming. The infrared Very Large Telescope (center) traces bright, warm material, and Hubble (right) reveals the optical and near-infrared glow of illuminated material. The central proto-stars provide ionizing radiation here; in denser protostellar environments, external radiation can be important as well. JWST will observe some ~50 protoplanetary disks during its first year of science operations.

Young protoplanetary disks are huge, spanning multiple times the Sun-Neptune distance.

This ALMA image showcases the face-on protoplanetary disk TW Hydrae. The illuminated fraction of the disk is a little over 100 Astronomical Units (A.U.) in diameter, or a little more than three times the Sun-Neptune distance. With a Neptune-sized array, we’d be able to see the tiny, Earth-sized exoplanets, even those located extremely close to the newly-forming star, in this radio data. This will require significant advances in timing.

One of them, Orion 294-606, was just imaged by the James Webb Space Telescope (JWST).

The original image of proplyd Orion 294-606 came from the Hubble Space Telescope (left); the same disk has now been imaged by the JWST (right), in higher resolution, greater detail, at longer wavelengths, and with more “bleeding” of external infrared light into the disk itself.

Background reflection nebulae are obscured by proplyds, creating silhouettes.

This selection of strongly silhouetted protoplanetary disks from within the Orion Nebula was published in 2000, back when 38 of Orion’s proplyds were then known. At present, some ~150 are now known.

JWST’s wider-field views showcase the loneliness of these individual systems.

This wider-field view of the proplyd Orion 294-606 comes from the James Webb Space Telescope’s NIRCam instrument, observing at a wavelength of ~1870 nm, corresponding to a strong infrared emission/absorption line of hydrogen. The two nearest stars are only tenths of a light-year away in this flattened image, but are actually more than a light-year away each in three dimensions. The separation distances between young planet-rich systems, even within star-forming regions, can be surprisingly large.

The nearest recently-formed stars are still nearly a full light-year away.

Despite the tremendous number of bright spots and illuminated gas/dust by the ESA’s Herschel and NASA’s WISE infrared space telescopes, the rich set of objects in this relatively small region are actually separated by significant distances. Nearby any one particular star or stellar system, except in the densest regions of all, star systems do not overlap, instead finding themselves separated by quite large distances relative to the scale of any particular planetary system around them.

Even in dense, actively star-forming regions, individual star-systems experience isolation, remaining unaffected by one another.

This glimpse into the stars found in the densest region of the Orion Nebula, near the heart of the Trapezium Cluster, shows a modern glimpse inside a star-forming region of the Milky Way. However, star-formation properties vary over cosmic time, from galaxy to galaxy, at different radii from the galactic center, etc. All of these properties and more must be reckoned with to compare the Sun with the overall population of stars within the Universe. Note that our Sun, born 4.6 billion years ago, is younger than 85% of all stars.

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