Roche lobe plots

For all the following I’m using gnuplot.

Isopotential curves

roche2d1

a=1
q=0.4
f(x,y)=2/(((x**2+y**2)**2)*(1+q)) +2*q/((((x-a)**2+y**2)**2)*(1+q)) +(x – q/(1+q))*
*2 +y**2
set view 0,0,1.3
set xlabel “x”
set ylabel “y”
set contours
set isosamples 100,100
set size ratio -1
unset surface
set cntrparam levels disc -2.2,-2.5,-3.55,-29.7,-100,-1000
unset ztics
splot [x=-6:6] [y=-6:6] -f(x,y)