Due to gravity the clouds will start to shrink. The infalling masses accelerate and will heat up. The cloud begins to radiate in the infrared wave lengths and is then in the protostar phase.
After 100,000 years or so the core density and temperature will become high enough so that nuclear fusion can start. This is called the T Tauri phase named after the stars for which this was first discovered. At this time the star is still surrounded by dust and gas, which will be slowly blown away by the radiation pressure.
Deep inside the core of the young star Hydrogen is being converted into Helium. This "burning" of Hydrogen produces a counter pressure to gravity that will stop the gas cloud from further shrinking. The gas cloud becomes a stable star. This is the present state of our Sun.
A protostar is a large object that forms by contraction out of the gas of a giant molecular cloud in the interstellar medium. The protostellar phase is an early stage in the process of star formation. For a solar-mass star it lasts about 100,000 years. It starts with a core of increased density in a molecular cloud and ends with the formation of a T Tauri star, which then develops into a main sequence star. This is heralded by the T Tauri wind, a type of super solar wind that marks the change from the star accreting mass into radiating energy.
Observations reveal that giant molecular clouds are approximately in a state of virial equilibrium—on the whole, the gravitational binding energy of the cloud is balanced by the thermal pressure of the cloud's constituent molecules and dust particles. Although thermal pressure is likely the dominant effect in counteracting gravitational collapse of protostellar cores, magnetic pressure, turbulence and rotation can also play a role (Larson, 2003). Any disturbance to the cloud may upset its state of equilibrium. Examples of disturbances are shock waves from supernovae; spiral density waves within galaxies and the close approach or collision of another cloud. If the disturbance is sufficiently large, it may lead to gravitational instability and subsequent collapse of a particular region of the cloud.
Answers & Comments
Verified answer
It all starts with a cloud of gas.
Due to gravity the clouds will start to shrink. The infalling masses accelerate and will heat up. The cloud begins to radiate in the infrared wave lengths and is then in the protostar phase.
After 100,000 years or so the core density and temperature will become high enough so that nuclear fusion can start. This is called the T Tauri phase named after the stars for which this was first discovered. At this time the star is still surrounded by dust and gas, which will be slowly blown away by the radiation pressure.
Deep inside the core of the young star Hydrogen is being converted into Helium. This "burning" of Hydrogen produces a counter pressure to gravity that will stop the gas cloud from further shrinking. The gas cloud becomes a stable star. This is the present state of our Sun.
A protostar is a large object that forms by contraction out of the gas of a giant molecular cloud in the interstellar medium. The protostellar phase is an early stage in the process of star formation. For a solar-mass star it lasts about 100,000 years. It starts with a core of increased density in a molecular cloud and ends with the formation of a T Tauri star, which then develops into a main sequence star. This is heralded by the T Tauri wind, a type of super solar wind that marks the change from the star accreting mass into radiating energy.
Observations reveal that giant molecular clouds are approximately in a state of virial equilibrium—on the whole, the gravitational binding energy of the cloud is balanced by the thermal pressure of the cloud's constituent molecules and dust particles. Although thermal pressure is likely the dominant effect in counteracting gravitational collapse of protostellar cores, magnetic pressure, turbulence and rotation can also play a role (Larson, 2003). Any disturbance to the cloud may upset its state of equilibrium. Examples of disturbances are shock waves from supernovae; spiral density waves within galaxies and the close approach or collision of another cloud. If the disturbance is sufficiently large, it may lead to gravitational instability and subsequent collapse of a particular region of the cloud.