Protostar

Definition

A protostar is an early stage in the formation of a star, where gas and dust collapse under gravity. It is characterized by the accumulation of material from a surrounding molecular cloud.

5 Must Know Facts For Your Next Test

1. Protostars form within molecular clouds called stellar nurseries.
2. The temperature and pressure within a protostar rise as it gathers more mass.
3. Protostars are not yet hot enough to initiate nuclear fusion.
4. They emit radiation primarily in the infrared spectrum due to their relatively cool temperatures compared to mature stars.
5. The protostar phase lasts for roughly 100,000 years before progressing to a main-sequence star.

Review Questions

• What conditions are necessary for a protostar to form?
• Why do protostars emit infrared radiation rather than visible light?
• How long does the protostar phase typically last?

Related terms

Molecular Cloud: A cold, dense region of gas and dust where new stars are born.

Main-Sequence Star: A stable star that has begun nuclear fusion in its core, converting hydrogen into helium.

Hydrostatic Equilibrium: The balance between gravitational force and internal pressure within a star, preventing collapse or expansion.