Number of Stars per Co Moving Unit Volume?
How many stars are there per Gpc^3 Co Moving Volume of the Universe?
I entered numbers into Ned Wright's calculator to find Co Moving
volumes (and radii) for the universe at different z values, in 1Gyr
increments back to 13 Gyrs in the past. I got the following values
using the default settings and "General" button, (which I think
includes the acceleration to the expansion of the universe due to
Dark Energy):
Co
Moving
Volume
Gpc^3
0.134
1.205
4.571
12.252
27.232
53.97
99.348
174.105
296.192
497.486
842.187
1484.868
2997.275 at Universe age - 0.721 Gyrs / z=3D7.368
If there are about 100E9 stars per galaxy and 100E9 galaxies in
universe, do I essentially have
1.0E22 stars per 2997 Gpc^3?
ie, rho_stars ~ 3.34E18 stars / Gpc co moving volume?
So that for each co moving volume above, I can multiply by this
value to get the number of stars within each co moving volume?
Ross
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