Properties of the Major Burning Stages of a 25 Solar Mass Star

Burning Stage
L_γ(W)

L_ν(W)

Temperature(K)

Radius(km)

Time

hydrogen==>helium

3.1x10³¹

....

39,800

4.2 million

7.4 million years

helium===>C,O

9.5x10³¹

7.3x10²⁷

15,800

47 million

680,000 years

carbon===>Ne,Na

1.2x10³²

10³³

4,360

670 million

170 years

neon===>O(??)

1.2x10³²

7.8x10³⁵

4,360

670 million

1.3 years

oxygen===>Si,P,S

1.2x10³²

2.3x10³⁶

4,360

670 million

0.52 years

silicon==>Fe-peak

1.2x10³²

3.8x10³⁸

4,360

670 million

1.4 days

collapse

1.2x10³²

8.1x10⁴¹

4,360

670 million

0.35 seconds

The luminosity of the Sun is 4x10²⁶ W
The diameter of the Sun is 1.4 million km
One year is ~31 million sec
Note that after the onset of carbon burning, the Luminosity, Radius, and Temperature of the star do not change ===> we cannot tell (from visual observations) in what stage of nuclear burning the star sits. Carbon burning 170 years. The stages after carbon burning take around 1 year!

Burning Stage

Lγ(W)

Lν(W)

Temperature(K)

Radius(km)

Time

hydrogen==>helium

3.1x1031

....

39,800

4.2 million

7.4 million years

helium===>C,O

9.5x1031

7.3x1027

15,800

47 million

680,000 years

carbon===>Ne,Na

1.2x1032

1033

4,360

670 million

170 years

neon===>O(??)

1.2x1032

7.8x1035

4,360

670 million

1.3 years

oxygen===>Si,P,S

1.2x1032

2.3x1036

4,360

670 million

0.52 years

silicon==>Fe-peak

1.2x1032

3.8x1038

4,360

670 million

1.4 days

collapse

1.2x1032

8.1x1041

4,360

670 million

0.35 seconds

L_γ(W)

L_ν(W)

3.1x10³¹

9.5x10³¹

7.3x10²⁷

1.2x10³²

10³³

1.2x10³²

7.8x10³⁵

1.2x10³²

2.3x10³⁶

1.2x10³²

3.8x10³⁸

1.2x10³²

8.1x10⁴¹