Table of Contents
What determines the life cycle a star will take?
A star’s life cycle is determined by its mass. The larger its mass, the shorter its life cycle. When the hydrogen supply in the core begins to run out, and the star is no longer generating heat by nuclear fusion, the core becomes unstable and contracts.
What does the end of a star’s life depend on?
The events at the end of a star’s life depend on its mass. Really massive stars use up their hydrogen fuel quickly, but are hot enough to fuse heavier elements such as helium and carbon. Once there is no fuel left, the star collapses and the outer layers explode as a ‘supernova’.
What causes a star to become a giant?
The fusion of hydrogen to form helium changes the interior composition of a star, which in turn results in changes in its temperature, luminosity, and radius. Eventually, as stars age, they evolve away from the main sequence to become red giants or supergiants.
What is the single most important characteristic in determining the course of a star’s evolution?
Mass is the single most important property of a star. It determines the evolution of a star as well as its lifetime (e.g. lower mass stars live longer).
The larger its mass, the shorter its life cycle. A star’s mass is determined by the amount of matter that is available in its nebula, the giant cloud of gas and dust from which it was born.
What happens to a star at the end of its life?
The core is stabilized and the end is near. The star will now begin to shed its outer layers as a diffuse cloud called a planetary nebula. Eventually, only about 20% of the star�s initial mass remains and the star spends the rest of its days cooling and shrinking until it is only a few thousand miles in diameter.
How is the luminosity of a StAR related to its fuel?
One can derive a reasonably accurate formula pretty quickly. The amount of fuel a star has is proportional to its mass (obvious, if you think about it). Meanwhile, it turns out that the luminosity of the star scales as L ∝ M 3.5. Now, stars are luminous because they burn their fuel (hydrogen).
How does the mass of a star keep it intact?
For a star, everything depends on its mass. Throughout their lives, stars fight the inward pull of the force of gravity. It is only the outward pressure created by the nuclear reactions pushing away from the star’s core that keeps the star “intact”.