File:Exoplanet Density-Radius Scatter.png

Adding material of density d to a planet of density D and radius R until it has radius r results in a planet with density:

${\displaystyle {\frac {(D-d)(4\pi /3)(R^{3})+(d)(4\pi /3)(r^{3})}{(4\pi /3)(r^{3})}}=(D-d)(R^{3})\cdot {\frac {1}{(r^{3})}}+d}$

The green lines are:

0.5-0.9: Rock and Iron: (3.6-3.34*1.45)*(0.5^3)*(r^-3) + 3.34*1.45

D=3.6, d=3.34*1.45, R=0.5

0.9-1.5: Rock and degenerate Iron: (4.8-3.34*2)*(0.9^3)*(r^-3) + 3.34*2

D=4.8, d=3.34*2, R=0.9

The blue line is:

1.5-4: Water: (6.1-1.15)*(1.48^3)*(r^-3) + 1.15

D=6.1, d=(1+0.15) R=1.48

The purple line is:

4-6: Water + Methane: (1.4-(0.782))*(4.11^3)*(r^-3) + 0.782

D=1.4, d=(0.682+0.1), R=4.11

The red line is:

6-10.5: Water + Methane: 0.005*r^3-0.0942857*r^2+0.613571*(r) - 0.337714 (Cubic fit)

The orange line is:

10.5-30: Hydrogen: (1.5-0.0708)*(10.5^3)*(r^-3) + 0.0708

D=1.5, d=0.0708, r=10.5

The yellow lines are:

2-6: Giants: (7-0.522)*(2^3)*(r^-3) + 0.522

D=4, d=(0.422+0.1), R=2.7

6-11.5: Giants: 0.00333*r^3-0.0632143*r^2+0.375595*r + 0.0517143 (Cubic fit)

See also:

• File:Exoplanet Density-Radius Scatter.png
• File:Planetary interior structure.png
• File:Water world interior structure.png
• File:Gas Giant interior structure.png
• File:Exoplanet Escape velocity-Radius Scatter.png
• File:Exoplanet Gravity-Radius Scatter.png
• File:Exoplanet Orbits.png
• File:Exoplanet systems.png
• File:Rapidly spinning planet.gif

Created with Matplotlib

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