protoplanetary
/ˌproʊtoʊˈplænɪˌtɛri/
adjective
- Relating to the early stage of planet formation, before planets are fully formed.
- Scientists study protoplanetary systems to understand how Earth was born.
- The protoplanetary disk around the young star contained gas and dust.
- Telescopes captured images of a protoplanetary cloud swirling in space.