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Article Index

Summary

As we saw, the mass of the star is the most important factor that determines its evolution. The diagram below illustrates stellar evolution of stars of increasing mass from bottom to top (Click image for source and larger version).

 

stellar evolution

 

Summary of different outcomes in the final stage of stellar evolution.


Original Mass

Mass of End Stage

Type

Stable due to

< 0.8 Msun

< 1.4 Msun

White Dwarf (He)

Electron degeneracy pressure

< 4 Msun

White Dwarf (C, O)

< 8 Msun

White Dwarf (O, Ne, Mg)

8 – 18 Msun

1.4 – 3 Msun

Neutron Star

Neutron degeneracy pressure

> 18 Msun

3 - 20 Msun

Black Hole

No known force can withstand the gravitational pressure

 

Explanations
• The limit of 1.4 Msun is called the Chandrasekhar limit
Electron degeneracy pressure is the resistance of electrons in atoms
against the collapse of the atomic structure
Neutron degeneracy pressure Is the resistance of the atomic nucleus
after electrons have been crushed into it, forming neutrons and neutrino's

 

Typical values for size and Escape Velocity (function of mass)

 

Radius

Escape Velocity

in speed of light (c)

 White Dwarf

~ 6000 km

~ 0.02 c

Neutron star

~ 10  km

~ 0.7 c

Stellar Black Hole

< 30 km (event horizon)

> c

 

Explore:

Interactive guide to Stellar Evolution

Virtual trip to Black Holes and Neutron Stars

Further Reading:

Download stellar evolution story here

Stellar Evolution

 

 

 

 

 

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