What heats a protostar?


What heats a protostar?

Life Cycle of a Star:

A star starts out life as a nebula or several nebulae that are rotating about each other. If the mass is large enough, it begins to pull in more mass and starts rotating about each other. As it spins and gain more mass it compresses, thus beginning the life of a star. If it coalesces enough, it becomes a protostar that continues to gain more mass. If there is enough interstellar material around the protostar, it begins to collapse due to its gravity. If the gravitational force is large enough to increase the temperature to the point that nuclear fusion could occur, a star is born. How a star dies would depend on the mass of the star, but they all start out as red giants then explode into a planetary nebula if it near the mass of our sun and end up as a white dwarf. If the mass is so much larger than the mass of our sun, after becoming a red giant it would explode into a supernova and end up either as a neutron star or theoretically a black hole.

Answer and Explanation:

A protostar is the mature star in its infancy stage. It is also rotating and pulling in interstellar material and starts to produce a bit of light. The gravitational pull of the forming core will continue to attract more material, several million tons of interstellar material colliding and spinning about creating a charged cloud. As these materials contract, the gas and dust particles continually collide with each other to the point that it nears the temperature that allows nuclear fusion to occur. It heats up as the gas particles and dust spin and collide with each other as it collapses to form the star. It has to exceed around 10 million Kelvins in order for nuclear fusion to occur.

It is rather hard to visualize how colliding dust particles could end up reaching a temperature that high. Imagine an enclosed room where there is no air conditioning but an electric fan is being used. After a few minutes with the fan on high, the room will actually be warmer instead of cooler. Imagine that happening in the vacuum of space with several trillion kilograms of dust and gas particles.

In space it is rather difficult to visually detect a protostar since it is often surrounded by a cloud of dust and gas. In later stages, around 100,000 to several million years, the flat disk that is the protostar can be seen, spewing out the gas particles it cannot attract anymore. This disk of gas particles could further compress into planets and other satellites.

Learn more about this topic:

Protostar: Definition, Formation & Facts

from Intro to Astronomy: Help and Review

Chapter 16 / Lesson 7

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