it depends how far away the star is. it's not like we have the technology or anything anyway so....
Yes, the core of a high mass star will collapse under immense gravitational pressure during a supernova explosion, forming a neutron star. Neutron stars are incredibly dense and composed primarily of neutrons, hence the name.
That depends on how far away the star is. If the exploding star is 1,000 light years away we would see the supernova 1,000 years later. If it is 2,000 light years away we would see it 2,000 years later.
Star
The time it takes for a star to move 15 degrees across the sky depends on its rate of motion (angular speed). Without knowing this speed, it is not possible to determine the exact time you have been watching the star.
size
I think it´s mass.
The lifetime of a star depends on the amount of fuel a star has, and the rate at which it fuses it. This can better be described as it's mass and it's luminosity.
The lifetime of a star depends on the amount of fuel a star has, and the rate at which it fuses it. This can better be described as it's mass and it's luminosity.
I assume you mean, "how long a star lives". That depends mainly on the star's mass, with more massive stars using up their fuel way faster than less massive ones.
size
the stars amount of mass
Stars live different lengths of time, depending on how big they are. A star like our Sun lives for about 10 billion years, while a star which weighs twenty times as much lives only 10 million years, about a thousandth as long.
It's luminosity,motion and mass.
it depends how far away the star is. it's not like we have the technology or anything anyway so....
It depends on the size of the star forming. For a one solar-mass star it lasts about 1,000,000 years.
The death sequence of a star is primarily determined by its mass. Low to medium mass stars end their lives as white dwarfs, while massive stars can go supernova and collapse into neutron stars or black holes. The specific fate of a star depends on the balance between internal pressure and gravitational forces.