Scientists Just Witnessed the Birth of a Solar System for the First Time

JeremySci/Tech2025-07-227310

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Observations of the young HOPS-315 star system show an environment analogous to what our own nascent Solar System would have looked like billions of years ago.

The star is surrounded by a protoplanetary disk, and this disk is the first evidence of debris condensing into what will eventually become planets and other objects.

Observing this early phase of evolution around a protostar will allow scientists to learn more about the formation of our own Solar System.

If our Solar System had baby pictures from over 4.5 billion years ago, they would look something like the otherworldly swirls of dust and gas surrounding the young star HOPS-315.

Nascent planets forming around young stars have been observed before, but until now, what hasn’t been seen is the phase of star system formation before that, when mineral particles condense at extreme temperatures from a protoplanetary disk to form what will later become those new planets. The enormous surrounding clouds of gas and dust tend to obscure what was going on.

But NASA’s James Webb Space Telescope (by making observations at infrared and millimeter wavelengths) has finally revealed chemical signals that are, for a star system, what ultrasound images are for human pregnancies. The sources for these signals were crystalline minerals floating in hot silicon monoxide (SiO) gas in the inner region of the protoplanetary disk around HOPS-315. The star and its disk are located 1,300 light-years away, which means we are seeing them as they existed during humanity’s year 700. And because a thousand years is a blink of an eye in cosmic terms, HOPS-315 is probably still a developing protostar.

When an international team of researchers found out about the Webb observations, they zeroed in with ESO’s Atacama Large Millimeter Array (ALMA) and captured the moment that minerals (which had sublimated in the intense heat, meaning that they evaporated without turning liquid) started to condense into planetary embryos.

“The first high-temperature minerals to recondense from this gaseous reservoir start the clock on planet formation,” said the team (led by astronomer Melissa McClure of Leiden University in the Netherlands) in a study recently published in the journal Nature.

This is what McClure goes on to call a “t=0 moment” in the creation of a new planetary system. When she and her team compared their findings with models of how our Solar System came into being, they found that the formation of solids from cooling gases and mineral dust in the HOPS-315 system mirrored what is thought to have happened in our own stellar territory. The materials that form from the early phases of this process are known as refractory solids, which can survive intense heat without degrading. When our Solar System was forming, the temperature around proto-Earth is thought to have been around 327 degrees Celsius (620 degrees Fahrenheit).

Remnants of the first solids that ever condensed in this region of our Solar System can be found embedded in primordial meteorites that have crashed to Earth, taking the form of flecks of minerals. Some of these flecks are even older than the Solar System itself—the presolar grains in the Murchison meteorite, for instance, go back 7 billion years. They are thought to have come from the remains of ancient stars that were swept through the interstellar medium, forming a new nebula that eventually flattened into the protoplanetary disk from which our Solar System emerged.

“Comparison with condensation models with rapid grain growth and disk structure models suggests the formation of refractory solids analogous to those in our Solar System,” McClure said. And if the HOPS-315 system continues to evolve as our own system did, minerals will collide and stick to each other until they form larger and larger rocks, which will accrete into planetesimals and, eventually, actual planets.

We’ll just have to keep watching and learning.