Well usualy a maya user would avoid this situation in the firtsplace (because they would have created the planets aligned).
Because:
if you create one planet and hit "D" (yes thets big d not small one), move planet 2 thats now created, newer clear the selection, hit "D" 6 more times violka youve created a distributed string of planets.
But:
yes in the modify menu theres the
Modify->Snap Align Objects->Align Objects
(yes this means you should choose the box next to the item, not the menuitem itself)
and use the dist option
Tip: learn to use, the find menu command in the help menu, paset following and execute:
CODE
findMenuItem;searchAllMenus ("find");