Stellar Evolution Page 13


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.

Source: http://chandra.harvard.edu/edu/formal/stellar_ev/


We have discussed three different outcomes in the final stage of stellar evolution.
The table gives a summary of these outcomes.

Original Mass

Mass of Core at end of Red Giant stage


Stable due to

< 8 Msun

< 1.4 Msun

White Dwarf

Electron degeneracy pressure

1.4 – 3 Msun

Neutron Star

Neutron degeneracy pressure

> 8 Msun

> 3 Msun

Black Hole

No known force can withstand the gravitational pressure


Typical values for mass and size:




 White Dwarf

Size of Earth

< 1.4 x Msun

Neutron star

30 km

1.4 - 2.1 x Msun

Stellar Black Hole

30 km (event horizon)

up to 100 x Msun

Super massive black holes can have a mass of many million, even billion times Msun. The largest detected super massive black hole to date has an estimated mass of 18 billion (1.8x1010) Msun. Ref...