Why in news?
Astronomers using the James Webb Space Telescope (JWST) and the Atacama Large Millimeter/submillimeter Array (ALMA) reported the first observation of hot gas condensing into solid rock around a newborn star, named HOPS‑315, located about 1,300 light‑years away in the Orion molecular cloud.
What was observed?
- Proto‑star and disc: HOPS‑315 is a young protostar surrounded by a dense disc of gas and dust. The disc is tilted in a way that gives Earth‑based telescopes an unobstructed view of its inner region.
- Condensation of minerals: JWST detected silicon monoxide gas and crystalline silicates within about 2.2 astronomical units of the star – a region comparable to the asteroid belt in our Solar System. At around 1 AU the gas vapourised at roughly 1,300 K and re‑condensed into minerals such as forsterite and enstatite.
- ALMA confirmation: ALMA observations showed that the crystals were embedded in the disc rather than being part of stellar jets. The absence of slow‑moving silicon monoxide outside the disc confirmed the crystals’ in‑situ formation.
Why is this important?
- Direct evidence of planet formation: Scientists witnessed the earliest step in the formation of rocky planets – vapourised rock condensing into solid grains.
- Window into our past: The process mirrors what happened in the early Solar System, helping us understand how Earth and other terrestrial planets originated.
- Rare observational opportunity: The unique tilt of HOPS‑315’s disc allowed instruments to peer deep into its interior, a feat rarely possible with other young stars.