Question

star
nebula
protoplanetary disk
gravitational collapse
protostar
a large, cloud - like structure in space—mostly made of gas and dust—from which stars can form
a flattened, rotating cloud of gas and dust surrounding a newly formed star, from which comets, asteroids, and planets can form
an extremely hot, dense celestial object with high enough core temperature and pressure for hydrogen atoms to fuse into helium atoms
the inward contraction of a cloud of gas and dust as it gets more massive and its gravity increases
a hot, dense celestial object formed when a cloud of gas and dust collapses in on itself due to gravity

Explanation:

Match each term to its definition based on stellar formation concepts:

1. The first definition describes a cloud of gas/dust for star formation, which is a nebula.
2. The second definition refers to a flattened disk around a new star for planet formation, which is a protoplanetary disk.
3. The third definition is a celestial object with hydrogen fusion, which is a star.
4. The fourth definition is the inward contraction of a gas/dust cloud, which is gravitational collapse.
5. The fifth definition is a hot dense object from cloud collapse, which is a protostar.

Answer:

nebula - A large, cloud-like structure in space—mostly made of gas and dust—from which stars can form
protoplanetary disk - A flattened, rotating cloud of gas and dust surrounding a newly formed star, from which comets, asteroids, and planets can form
star - An extremely hot, dense celestial object with high enough core temperature and pressure for hydrogen atoms to fuse into helium atoms
gravitational collapse - The inward contraction of a cloud of gas and dust as it gets more massive and its gravity increases
protostar - A hot, dense celestial object formed when a cloud of gas and dust collapses in on itself due to gravity