How long does the Subgiant phase last?
The core contraction and envelope expansion is very rapid, taking only a few million years. In this time the temperature of the star will cool from its main sequence value of 6,000–30,000 K to around 5,000 K.
How long do Subgiant stars live?
Subgiant phase Depending on the mass of the helium core, this continues for several million to one or two billion years, with the star expanding and cooling at a similar or slightly lower luminosity to its main sequence state.
What does an HR diagram describe?
Hertzsprung-Russell diagram, also called H-R diagram, in astronomy, graph in which the absolute magnitudes (intrinsic brightness) of stars are plotted against their spectral types (temperatures). The most massive stars explode in supernovas.
Is the sun on the Zero Age main sequence?
The track for a 1-solar-mass star shows that the Sun is still in the main-sequence phase of evolution, since it is only about 4.5 billion years old. It will be billions of years before the Sun begins its own “climb” away from the main sequence—the expansion of its outer layers that will make it a red giant.
Are AGB stars red giants?
AGB stage. During the E-AGB phase, the main source of energy is helium fusion in a shell around a core consisting mostly of carbon and oxygen. During this phase, the star swells up to giant proportions to become a red giant again. The star’s radius may become as large as one astronomical unit (~215 R ☉).
What are the stages of stars?
The formation and life cycle of stars
- A nebula. A star forms from massive clouds of dust and gas in space, also known as a nebula.
- Protostar. As the mass falls together it gets hot.
- Main sequence star.
- Red giant star.
- White dwarf.
- Supernova.
- Neutron star or black hole.
What is a star’s life cycle?
A star’s life cycle is determined by its mass. 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.