12 billion years
Once the gases start to coalesce and produce heat and light from friction, rather fusion (This is called a Proto-Star). That generally lasts about 150,000 years then nuclear fusion starts and a true star is formed.
It depends on the size of the star forming. For a one solar-mass star it lasts about 1,000,000 years.
Oliver Small you are a star
infinite years
Vega will be the north star in about 12,000 years time.
A star with the same mass as the Sun can fuse hydrogen in its core for about 10 billion years. After exhausting its hydrogen fuel, it will then enter the helium fusion phase, which lasts for around 100 million years. Therefore, while hydrogen fusion dominates its life, helium fusion is a much shorter process.
A neutron star is smaller, but has a greater mass. A typical white dwarf is about the size of a terrestrial planet. A typical neutron star is a few miles across.
It is estimated that a star like the Sun may last about 15 to 20 billion years, although less than half of that in its current active form. About halfway through its lifespan, a typical yellow star will begin to expand into a red giant. Ultimately, it will form a dwarf star. Stars last anywhere from about a million years to several trillion years. It depends on the star's mass; higher-mass stars live for less time. Once a star becomes a white dwarf, or a neutron star, it no longer supports fusion. But it will remain at a very high temperature (thousands of kelvins) for many billions of years.
no but it will be in many years
10 years.
7 years
It can be as old as 10 billion years. Then it increases to the size of a giant and supernova. After that it turns into a small dense white dwarf.