In a remarkable breakthrough, astronomers have for the first time witnessed the very beginning of a solar system forming around a young star named HOPS‑315—a glimpse into what our own solar system may have looked like some 4.5 billion years ago.
Located approximately 1,300 light-years from Earth, HOPS-315 is still in its infancy, about 100,000 to 200,000 years old. Observations show it is surrounded by a disc of gas and dust—the raw material for planets—that is already beginning to crystallize into solid minerals.
Using data from the James Webb Space Telescope (JWST) and the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, researchers detected signatures of hot gas—specifically silicon monoxide (SiO)—and crystalline silicate minerals condensing out of the gas phase. These are the very first building blocks of rocky worlds.
What makes this discovery historic is the stage at which the system is being observed. Whereas previous studies of exoplanet formation often captured disks already showing gaps carved by emerging planets, the HOPS-315 system shows no planets yet—we’re seeing the moment before proto-planets even form. It’s the earliest stage captured to date.
The region where these minerals are forming lies at a distance from the star similar to where the asteroid belt lies in our own Solar System. That suggests HOPS-315 is a compelling analogue for the very early Solar System.
One of the lead researchers put it plainly: “We’re seeing a system that looks like what our Solar System looked like when it was just beginning to form.”
The process of planet-forming begins with dust and gas in a protoplanetary disk. At high temperatures near the star, minerals like silicates condense out of the gas; these then accumulate, stick together, grow into planetesimals, and eventually full-blown planets. What makes HOPS-315 special is that we’re seeing those very first condensed minerals—materials that later go on to form Earth-like worlds.
Scientists say that this observation helps fill in a major piece of the puzzle: how the first solid bits in a planetary system form and evolve, bringing us closer to understanding how our own planet and neighbours came into being. Up until now, these earliest stages were theorised but rarely observed definitively.
Looking ahead, researchers plan to keep watching HOPS-315, imaging how the condensation region changes, whether water and ices begin to appear further out in the disk, and how the solid grains grow. This will tell us more about how rocky planets (and perhaps habitable ones) get their start.
In short: this discovery isn’t just another exoplanet candidate. It’s a live snapshot of the very beginning of a planetary system—our best opportunity yet to see how worlds like Earth might begin.
Source:
McClure M. et al., Refractory solid condensation detected in an embedded protoplanetary disk, Nature (2025). Reported via ALMA/ESO press release; University of Michigan; ScienceFocus; EarthSky.