A disk so vast that it could contain forty solar systems like our own: this colossal structure has been uncovered by astronomers observing a planetary nursery around a young star, an environment much more chaotic and disordered than scientists had imagined.
Images from the Hubble Space Telescope reveal for the first time in visible light this giant formation named IRAS 23077+6707. Its width reaches nearly 250 billion miles (400 billion kilometers), a dimension that places it far ahead of all known similar disks. This extraordinary size even obscures the central star, which could be single or form a close pair. The whole evokes a cosmic sandwich, with a dark band surrounded by bright layers of gas and dust.
What particularly intrigues researchers is the marked asymmetry of the disk. On one side, long filaments rise high above the plane, while the other side presents a sharp edge without these structures. This unbalanced arrangement shows that external processes, recent infalls of material, or interactions with the environment are actively shaping this planetary cradle.
The largest planetary formation disk ever imaged, observed by Hubble. It extends over a distance equivalent to 40 times the diameter of our Solar System.
Credit: NASA, ESA, STScI, Kristina Monsch (CfA) ; Image Processing: Joseph DePasquale (STScI) The disk's mass is estimated to be between ten and thirty times that of Jupiter, providing enough material to spawn several gas giants. This makes it an enlarged analogue of our young Solar System, offering a unique opportunity to study the birth of worlds in a massive environment.
The team, led by Kristina Monsch, has published this data in
The Astrophysical Journal. They indicate that the precision of Hubble's images allows details rarely visible to be distinguished. The amusing nickname 'Chivito de Dracula' blends the researchers' origins, evoking both Transylvania and an Uruguayan sandwich.
Protoplanetary disks, cradles of worlds
Around young stars, disks of gas and dust slowly rotate. These structures, called protoplanetary disks, are the places where planets are born. They form from the initial cloud that gave birth to the central star, and their composition reflects that of this original cloud.
Over time, dust particles clump together to form pebbles, then planetesimals. These small bodies collide and gradually assemble under the effect of gravity. This process can last several million years, leading to the creation of rocky planets like Earth or cores for gas giants.
The size and mass of these disks vary enormously. Some, like the one observed by Hubble, are immense and very massive, suggesting they could produce very extensive planetary systems. Others are more modest, similar to what our own Solar System probably was in its youth.
Studying these disks allows us to trace the stages of planetary formation.
The formation of gas giants
Giant planets like Jupiter or Saturn form differently from rocky worlds. Their creation begins with the accretion of a solid core from ices and rocks present in the protoplanetary disk. Once this core is massive enough, it attracts the surrounding gas by gravity.
This process requires specific conditions. The disk must contain enough gas and be cold enough for volatile elements to condense. The presence of gas giants in a system also influences the formation of other planets, as their gravity can disrupt orbits and the distribution of matter.
In very massive disks like IRAS 23077+6707, the amount of available material potentially allows for the birth of several giants. However, the observed turbulence could alter classic patterns, by scattering matter or creating zones of variable density.
Understanding these mechanisms helps explain the diversity of discovered planetary systems. Some stars host 'hot Jupiters', giants very close to their sun, while others possess distant giants.