where I have used Ticks -> {{{-0.75, "\[Pi]/4"}, 6, {-8, "Sun"}, 10}, {}, {}, {}},
to mark important points on the x-axis.
I would like to remove the tick marks under the Pi/4 and Sun labels, but don't know how to do this while retaining the labels.
If there is no way to do this, is there instead a way to label the x-axis without using Ticks as I have done?
For reference here is the code that establishes the axes:
shells = SphericalPlot3D[{6, 10}, {\[Theta], 0, Pi}, {\[Phi], 0,
2 Pi}, Mesh -> None, PlotPoints -> 50, ImageSize -> Large,
Boxed -> False, AxesOrigin -> {0, 0, 0},
PlotStyle -> {Directive[Gray, Opacity[0.05]],
Directive[Gray, Opacity[0.05]]},
PlotRange -> {{-14, 14}, {-14, 14}, {-14, 14}},
AxesLabel -> {"\!\(\*SubscriptBox[\(x\), \(g\)]\) [kpc]",
"\!\(\*SubscriptBox[\(y\), \(g\)]\) [kpc]",
"\!\(\*SubscriptBox[\(z\), \(g\)]\) [kpc]"},
AxesStyle -> Directive[Black, Bold, 15],
LabelStyle -> Directive[Black, Bold, 15],
Ticks -> {{{-0.75, "\[Pi]/4"}, 6, {-8, "Sun"}, 10}, {}, {}, {}},
TicksStyle -> Directive[{Opacity[1]}]
]
Note: FrameStyle is not an option for SphericalPlot3D.