Nuclear fusion produces heat, and heat creates the pressure which keeps the star from collapsing under its own gravity. The relationship between heat and pressure in a gas is described by the Ideal Gas Laws. It also applies to plasma (which can be described as a super heated gas).
hydrostatic
Dynamic equilibrium.
A star that was 150 solar masses would spend the main part of its life as a main sequence star before collapsing into a white dwarf. A stars mass determines the life expectancy as well as its probable cause of death.
The sun is a main sequence star
Sirius is not a single star but a binary star system consisting of a white main sequence star and a white dwarf.
hydrostatic
Hydrogen fusion to make helium. When a star runs out of hydrogen in its core to fuse, it begins collapsing, leaves the main sequence, then ignites helium fusion to make carbon, becoming a red giant.
Dynamic equilibrium.
No. Red giants are not on the main sequence.
A star that was 150 solar masses would spend the main part of its life as a main sequence star before collapsing into a white dwarf. A stars mass determines the life expectancy as well as its probable cause of death.
A red main sequence star would be a red dwarf or a branch red giant. To be on the main sequence, you have to have hydrogen nuclear fusion.
The sun is a main sequence star, so 1 AU.
The sun is a main sequence star
Main-Sequence star
Sirius is not a single star but a binary star system consisting of a white main sequence star and a white dwarf.
None of those is a main sequence star.
The defining characteristic of a main sequence star burns hydrogen to helium in its core.