One sphere from the props folder.
Set it at ambient_color white and put ambient_value at 1 to 10 to make it glow=> experiment.

Put a second sphere from the props folder around it at 110 to 120% scale.
Put some transparant on this second sphere and connect a cloud node to it.
Again experiment with the transparancy and the cloud node density to obtain the effect you are looking for.
=>The result will only be visible in the render. Do area renders to test your value's.

Some examples of this tip/trick have been shown here in the past.

Poser 1, 2, 3, 4, 5, 7, P8 and PPro2010, P9 and PP2012, P10 and PP2014 Game Dev
"Do not drive faster then your angel can fly"!