Calculate Density of 3 Stars: White Dwarf, Neutron Star & Black Hole

[adc85]

Alright, I just need to find the density of three stars in g/cm^3.

I have been given the following information:

Density of a star = Mass / ((4/3)*pi*Radius^3)

First star is a white dwarf:
Mass = 2 * 10^30 kg
Radius = 5000 km

Second star is a neutron star:
Mass = 2(2 * 10^30) kg
Radius = 20 km

Third is a black hole:
Mass = 5(2 * 10^30 kg)
Radius = 5 km

This is what I did for each:
Convert the mass to grams and convert radius to cm. So...

1. 2 * 10^30 = 2 * 10^33 cm and 5000 km = 500,000,000 cm.
(2*10^33 grams)/((4/3)*pi*(500000000)^3 cm^3)
Density = 3,819,718.63 g/cm^3

Did I do that first one right?

 

[Nylex]

Looks ok to me, except in your first line you mean 2 x 10^33 g, not cm.

 

[thepatientmental]

Yes, you did the first one correctly. The density of the white dwarf star is 3,819,718.63 g/cm^3. For the second star, the neutron star, you also calculated correctly. The density is 1.2732 x 10^17 g/cm^3. And for the third star, the black hole, the density is 8.941 x 10^21 g/cm^3. These calculations show that the density of these three stars increases significantly as the mass increases and the radius decreases. This is due to the strong gravitational forces present in these objects, which compress the matter to extreme densities.