ALMA peers inside a colossal edge on disk where giant planets may already be forming
Astronomers using the Atacama Large Millimeter/submillimeter Array found an unusually revealing target in “Gomez’s Hamburger,” a protoplanetary disk seen almost edge-on, where neatly layered gas and dust expose how giant planets may begin assembling deep within young planetary systems.
This artist's impression of the Gomez’s Hamburger system shows the stacked layers of gas and dust as they rotate around a young star. ALMA observations reveal a direct view of its vertical structure at millimeter wavelengths, allowing astronomers to map the location of the millimeter-sized dust grains, and several different gas-phase molecules, which have arranged themselves in the distinct layers. Credit: NSF/AUI/NSF NRAO/P.Vosteen
Astronomers using the Atacama Large Millimeter/submillimeter Array have obtained one of the clearest views yet of the internal structure of a planet-forming disk, revealing conditions that strongly favor the birth of giant planets at extreme distances from their host star.
The target is Gomez’s Hamburger, or GoHam, a young stellar system whose disk is viewed almost perfectly edge-on, offering a direct look at how gas and dust are layered as planets begin to take shape. The findings were presented in January 2026 at the American Astronomical Society meeting and are currently being prepared for peer-reviewed publication.
What makes GoHam exceptional is not only its orientation but its sheer scale. The gaseous disk extends to nearly 1 000 astronomical units in radius, equivalent to roughly 150 billion km (93 billion miles), placing it among the largest known planet-forming disks. Vertically, the gas rises several hundred astronomical units above and below the disk midplane, reaching tens of billions of km. This vast reservoir of material gives the system an unusually high capacity to form massive planets, potentially on wide orbits.
ALMA observations at millimeter wavelengths reveal the disk as a stacked structure of solids and gas. Millimeter-sized dust grains are confined to a remarkably thin and dense layer at the midplane, where gravity concentrates the heaviest material. Above and below this plane, gas dominates, creating a thick, inflated atmosphere around the dust layer. This direct separation between solids and gas is a textbook prediction of disk evolution models, but it is rarely observed so clearly.
Different molecules trace different heights within the disk. The lightest form of carbon monoxide, carbon 12 monoxide, occupies the highest layers, exposed to stellar radiation. Carbon 13 monoxide lies lower, in cooler and denser regions. Sulfur-bearing molecules such as carbon monosulfide and sulfur monoxide are found closest to the midplane, where shielding is strongest, and temperatures allow these species to survive. This chemical stratification closely matches theoretical expectations and provides strong confirmation that current models of disk physics capture the essential processes at work.
Beyond its size and clarity, GoHam shows compelling signs of active planet formation. The dust layer is not symmetric. One side of the disk is brighter and more extended, indicating a large-scale concentration of solids. Such asymmetries are commonly associated with vortices or pressure traps, structures that can halt inward drifting dust and allow it to accumulate. These dust-rich regions are prime sites for the rapid growth of planet-building material.
Even more intriguing is a one-sided arc of sulfur monoxide emission detected just outside the brightest dust region. The gas in this arc follows the disk’s rotation, showing it is dynamically linked to the disk rather than being an external feature. The arc aligns with a previously identified dense clump known as GoHam b, which has been interpreted as material collapsing under its own gravity. This makes GoHam b a strong candidate for one of the earliest observable stages of a massive planet forming far from its star.
At the same time, the disk is losing material. Faint, extended carbon monoxide emission is detected at large distances, particularly toward the northern side of the system. This emission is consistent with a photoevaporative wind, in which energetic radiation from the central star heats the gas enough for it to escape into space. Such winds play a critical role in disk evolution, gradually dispersing gas and setting time limits on how long giant planets can continue to accrete.
The combination of extreme size, vertical clarity, chemical layering, asymmetries, and gas loss makes GoHam a benchmark system. It allows astronomers to test, in a single object, how disks evolve from gas-rich structures into planetary systems. Observations like these help explain how giant planets observed on very wide orbits around other stars could form without migrating outward from inner regions.
GoHam demonstrates that under the right conditions, massive disks can naturally produce giant planets far from their host star while still undergoing dispersal. The system turns long-standing theoretical ideas into directly observable phenomena, offering one of the most complete snapshots yet of giant planet formation in action.
References:
1 ALMA Devours Cosmic “Hamburger,” Reveals Potential for Giant Planet Formation – NRAO – January 5, 2026
I’m a science journalist and researcher at The Watchers, contributing to the Epicenter edition, where I cover peer-reviewed scientific research and emerging discoveries across Earth and space sciences. With a background in astronomy and a passion for environmental science, I’ve worked in shark and coral conservation in Fiji, conducting reef and shark-behavior research, contributing to mangrove restoration, and earning PADI Open Water and Coral Reef Certifications. I bring a blend of scientific rigor and storytelling to illuminate the discoveries shaping our planet and beyond.
This “Cosmic Hamburger is an artist conception, Sorry it’s a nothing burger with out the original picture. get real or go home I say.