A protostar becomes a star when energy is released by the process of?

Answer 1

Massive clouds of hydrogen gas/dust are pushed together randomly by solar winds and over millions of years their weak gravitational forces pull them closer and closer, getting stronger and stronger as the protostar becomes more dense until it finally implodes violently, the pressure at it's core reaching temperatures of many millions of degrees, which is enough to cause thermonuclear reaction, thus igniting a new star.

Answer 2

A protostar shines via gravitational collapse. It may shine for as much as a million years before its core becomes sufficiently hot and dense for hydrogen fusion to occur. Once fusion takes place, letting the neutrinos fly, the star shines with the pure light of a true sun.

The variable is mass. A star with insufficient mass, such as a brown dwarf, may never ignite with fusion "fire."

Answer 3

The dividing line is usually considered to be when the accretion process stops and the T tauri wind begins. This is probably approximately coincident with the beginning of lithium fusion (a T tauri star is not yet hot and dense enough for hydrogen fusion to start).

Answer 4

The nebula contracts under the influence of the mutual gravity of all those atoms

and dust particles. As its size decreases, density increases, and central pressure

and temperature increase.

Answer 5

At first, stars are formed from a cloud of dust and gas in space known as a nebula.
Even though stars are not alive, they have different stages of development such as
birth, development and death. Telescopes and satellites help us learn more about the
birth of stars, and they help us understand more about the universe. They show us
how much we really don't know about stars and their development.

Newborn stars emerge from dense, compressed pockets of evaporating gaseous
globules (EGGs). This gas is thick enough to fall down under its own weight. As the
cloud gets slighter, it begins to spin gradually faster, forming young stars. After
millions of years after the collapse, the center of the cloud reaches great
temperatures. At around 15 million Kelvin, the hydrogen nuclei of it fuse, and form
helium in nuclear fusion. The process releases huge amounts of energy in heat and
light forms, and so a star is born. Stars usually have enough hydrogen in it to power
it for billions of years. Stars continuously grow as the gather more mass from their
surroundings.

Answer 6

The size of a star is determined by the amount of resources it has to "build" with.

A normal star will accumulate vast amounts of hydrogen until the pressure in the core is so great that nuclear fusion is initiated. At this point, the radiation created will "push" away any remaining hydrogen into the further regions of "it's" system, and the accumulation phase will have ended.

Supergiant stars, have vast amounts of hydrogen available, so the rate of accumulation is so great, that even when the core has started to fuse, billions of tons of hydrogen are continually accumulated.

However, there is a limit to how much hydrogen a star can accumulate. As a star accumulates more hydrogen, the pressure in the core becomes hotter and more nuclear fusion occurs. It then becomes a balancing act between gravity on the core at the temperature pressure on the outer envelope. Something has to give. And gravity wins. It is believed, that some stars may have too much mass, that instead of nuclear fusion, they collapsed directly into a black hole.

The other theory, is that with vast amounts of hydrogen available, it's a matter of competition as additional stars will form within the nebula, thus reducing the amount of available hydrogen to a single star.

So much so, that at the moment, the largest a star can be is about 300 times the mass of our Sun.

The most massive star found so far is R136a1 at around 265 solar masses.

See related question.

Answer 7

The nebula is made up of gases such as hydrogen, helium and dust. The cloud then shrinks, divides into smaller swirling clouds. As cloud collapses, energy is released, then heats up in the centre of cloud, then when reaching 10 million degrees approx or high, it ignites and becomes a protostar!

Answer 8

A star actually becomes a star when nuclear fusion begins in the core. Before that, it's just a gas cloud. This requires enough assimilation of hydrogen to create enough pressure - and therefore enough heat - to initiate nuclear chain reaction at the core. The tremendous outward power this nuclear reaction causes is balanced by the tremendous weight of hydrogen pushing down on the nuclear core. The result is what is known as "hydrostatic balance" - a perfect spheroid glowing ball of gas. A star is born.

Answer 9

In class we watched a video and the people said there is a explosions called the nova cloud and if any cloud gets in its way they the explosion will set off and that how we can they people said that all of that planets are stars.

Answer 10

A new star is born when heluim and oxyen combine together.