Paragus's method on killing Vegeta?

[Let's Go Fearless!]

Why couldn't he just let Broly deal Vegeta's death but instead he planned to trap Vegeta on a planet that will be destroyed anyway by some asteroid shit?

 

[Jeff Styles]

I have no in universe explanation... maybe because he wants Vegeta to freeze to death? Suffer the same fate as the other Saiyans?

 

[Let's Go Fearless!]

Could it be that he was afraid if Broly goes berserk kills Vegeta and couldn't control him again?

 

[SIAD]

I have always thought that any of them could eliminate the comet very easily.

 

[Captain Cadaver]

Most likely Broly's lack of control was too much of a gamble (especially considering what it eventually did to Paragus), so the comet was a far safer bet than putting himself at risk as well with his berserker of a son and even if he were to bank on Broly, it's a good Plan B.