The most common and most likely answer to this crossword clue is the 6 letter word URANUS
I've seen this crossword clue in Financial Times
U
R
A
N
U
S
More clues leading to the result URANUS
- For all to see, what FDR did for the world
- World University managed by American
- God in uniform was American president?
- God placing 6 and Egyptian equivalent back-to-back behind you
- Planet getting warmer as rage unleashed, initially, after uprising
- God‘s city, once a star’s retreat
- Ancient city originally associated by students with a mythological god
- World leader in uniform led fifty states
- Tour Iran, plus half the planet
- Managed university in America, part of the system we’re in
Buddy explains!

The straight part
We know that "Planet" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case planet = uranus.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.