The disk loses about one Earth mass per year
In the stellar nursery of the Orion Nebula, 1,400 light-years away, humanity's most powerful space telescope has witnessed a quiet tragedy: a young planetary disk being slowly unmade before it can become a world. The James Webb Space Telescope has shown that intense ultraviolet radiation from massive neighboring stars strips away the raw material of planet formation at a rate of one Earth-mass of gas per year — a process so relentless that gas giants like Jupiter can never coalesce around smaller, gravitationally weaker stars. The finding reframes our solar system's existence not as ordinary, but as the fortunate consequence of our sun's particular mass, and invites us to consider how many worlds were never permitted to begin.
- A protoplanetary disk called d203-506 is losing an entire Earth's worth of gas every year, hemorrhaging the very material planets are made from before they can form.
- The culprit is not chaos but proximity — massive stars tens of thousands of times more luminous than our sun flood the region with ultraviolet radiation that boils gas off the disk in a process called photoevaporation.
- The host star's low mass — just one-tenth that of our sun — means its gravity is too weak to hold the disk together against this radiation assault, making a Jupiter-like planet an impossibility.
- Our own solar system likely formed in a similarly hostile environment, yet Jupiter survived because our sun's greater mass gave it the gravitational authority to resist the same destructive forces.
- Discovered partly by accident through Hubble and ALMA observations before JWST's deeper gaze, the dataset is so rich that researchers estimate they have explored only 10 percent of what it contains.
The James Webb Space Telescope has peered into the Orion Nebula — the closest stellar nursery to Earth at roughly 1,400 light-years — and found a planetary system being quietly erased. The object, a young disk of dust and gas called d203-506, orbits a red dwarf star less than a million years old and possessing only about a tenth of our sun's mass. What JWST revealed was a disk under siege.
Nearby massive stars, some a hundred thousand times more luminous than our sun, flood the region with ultraviolet radiation that heats the disk's gas until it evaporates — a process known as photoevaporation. The disk loses roughly one Earth-mass of gas per year, and lead researcher Olivier Berné of the Institut de Recherche en Astrophysique et Planétologie concluded that this relentless stripping will prevent d203-506 from ever producing a gas giant like Jupiter.
This raises a pointed question: our own solar system is thought to have formed in a comparably harsh environment, yet Jupiter exists. The answer appears to lie in gravity. Our sun's greater mass gives it a stronger gravitational hold on its disk, enough to resist the radiation-driven losses that overwhelm the smaller star. Mass, it turns out, may be as decisive as any other factor in determining what kinds of worlds a star is permitted to build.
The discovery began almost by accident — d203-506 first appeared as a faint object in Hubble data, then glowed unexpectedly bright in observations from the Atacama Large Millimeter Array, prompting the team to train JWST on it. The resulting infrared spectra were so information-dense that a year after publication in the journal Science, researchers estimate they have examined only about 10 percent of what the data holds.
The James Webb Space Telescope has revealed something sobering about how planets get made—or fail to. Deep in the Orion Nebula, about 1,400 light-years from Earth, astronomers found a disk of dust and gas called d203-506 that is being systematically stripped of the material needed to birth large worlds. The culprit is radiation from nearby massive stars, a process so violent that it erases roughly one Earth's worth of gas from the disk every year.
The Orion Nebula is the closest stellar nursery to us, a vast cloud where new stars are still being born. Dust and gas there are thick enough to hide infant stars from ordinary telescopes, but infrared light passes through. That's why JWST, with its infrared eyes, could pierce the nebula's veil and focus on d203-506—a young planetary system in the making, orbiting a small red dwarf star less than a million years old and possessing only about 10 percent of our sun's mass.
What JWST found was a disk under siege. The host star itself is cool and mild, but the neighborhood is brutal. Massive stars nearby—some ten times the sun's size and 100,000 times more luminous—flood the region with ultraviolet radiation. This UV bombardment heats the disk's gas until it simply evaporates away, a phenomenon astronomers call photoevaporation. Olivier Berné, the lead researcher at the Institut de Recherche en Astrophysique et Planétologie, explained that this radiation-driven escape is so efficient it can suppress the formation of gas giants entirely. The disk d203-506 will likely never birth a Jupiter.
This raises a puzzle: our own solar system formed in what researchers believe was a similar environment—the ancient Orion Nebula or something like it—yet Jupiter emerged anyway. Why did our system survive what d203-506 cannot? The answer lies in gravity. A star's mass determines how strongly it can hold onto its disk against the assault of external radiation. Our sun, five to ten times more massive than d203-506's host star, has a gravitational grip strong enough to resist photoevaporation. The smaller star's weaker gravity cannot. Its disk simply cannot hold on to enough material long enough for a gas giant to coalesce.
The discovery was partly accidental. Berné and his team first spotted d203-506 as a faint object in Hubble observations, then noticed it shone brightly in data from the Atacama Large Millimeter Array in Chile. That brightness warranted a closer look with JWST. What they found astonished them. The infrared spectra were extraordinarily rich with information—so much so that a year later, the team estimates they have used only about 10 percent of what the data contains. The research, published in the journal Science on March 1, 2024, offers a window into planetary birth and death, and suggests that a star's own mass may be as important as the disk around it in determining what kind of worlds can form.
Notable Quotes
Massive stars that are 10 times the size of the sun are 100,000 times more luminous than the sun, and therefore they cast a strong UV radiation on the disks around nearby sun-like stars. This radiation heats up the gas, which then escapes from the disk from which planets are expected to form, a process which we call 'photoevaporation.'— Olivier Berné, Institut de Recherche en Astrophysique et Planétologie
The star of d203-506 is five to 10 times less massive than the sun. Therefore, it has a weak gravitational field, which means its disk cannot resist photoevaporation well. A star like the sun has a larger gravitational field, so it would be able to better resist photoevaporation.— Olivier Berné
The Hearth Conversation Another angle on the story
So JWST is looking at a disk that's actively losing gas. How fast are we talking about?
One Earth mass per year. That's not a slow leak—that's a hemorrhage. In a few million years, the disk will be gone.
And this is happening because of radiation from other stars nearby?
Exactly. Massive stars nearby are blasting ultraviolet light into the disk. The gas heats up and just escapes. It's called photoevaporation.
But our solar system formed in a similar place, right? So why did we get Jupiter?
Our sun is much more massive. Stronger gravity means it could hold onto its disk better, resist that same radiation pressure. A smaller star just can't compete.
So mass is destiny for planetary systems?
It seems to be a major factor. You need a star heavy enough to anchor the disk while it's being bombarded. Without that, you get a stripped-down system, no gas giants.
What else is hiding in that JWST data they haven't looked at yet?
They've only scratched the surface—maybe 10 percent of the useful information. There could be details about the disk's chemistry, its structure, how the gas is actually escaping. It's all there waiting.