Aliens in the superhero genre

I had an idea this morning on my way to work for a character I'm thinking of incorporating into the superhero story I've been failing miserably with for the last while. I'm thinking that a new character may help motivate me again.

Anyway, he's an alien and for various personal reasons has decided to settle down on earth. I haven't figured out a great deal about his species yet, but he has significant physical advantages over your average human, not to mention extensive combat training. Long story short, he's going to be recruited into the local superhero team.

I know there are alien superheroes in comics (Superman and Martian Manhunter come to mind), but I can't remember if them being aliens was common knowledge in their worlds. Can anyone fill me in there?

Is the answer common to all (or most) aliens in the genre, or does it vary on an individual basis?

Are there any notable comonalities that seem to affect whether it is kept a secret?

Which way do you think worked better, and why?

Anything else you think I should know about writing an alien superhero?

Thanks

It can go any way. In some settings, aliens and/or other supernatural/superpowered beings are a closely kept secret, while in others they're common knowledge. (And still others start off as the former and become the latter through plot.)

I'm personally kind of sick of worlds that are "just like Earth but there's secretly magic/aliens/vampires/whatever", as they seem a bit contrived to me to manage to keep this stuff secret in this day and age, but that's just me, as other people doubtless still love this sort of thing.

Moving to PLot Doctoring.

Is he a Human Alien like Superman, or a clearly non-human like the Manhunter? Then there's Ben Ten, who's human but can transform into many aliens.

Being an alien would probably not be a big secret in superhero mode. But it would be tough to pose as human without records in secret identity mode. If he goes to the grocery store as an alien, would there be people pelting fruit at him or waiting for him to mess up so they can deport him? Can he apply for a green card and possible citizenship?

Note that "space alien" may include "legal alien".

Honestly, you always want someone or a group of someones who has some type of leverage over your superhero. I like to tie in fictional ideas into the modern world. This way readers understand what's going on, but you leave enough mystery for them to want to figure out how it works.

For a superhero alien, I'm thinking your alien escaped from it's world because of something (maybe conflict, or technology needed to save it's own planet, etc). When it landed, some secret government organization covered it up and helped the superhero to blend in (cause they don't want a freaky alien making people panic). But with said information, some corrupt people in the organization broke away, and now has leverage to make the alien do things (probably evil) for themselves. But I'm sick of everyone knowing the superhero. I think my way would be an interesting concept, because he has multiple conflicts:
trying to fit into Earth, finding something for his planet, coinciding with the evil people's plans, finding who the evil people are, deciding what to do with them, trying to do right when the evil people are making him do bad things, getting in trouble with the good government cause he was caught doing stuff for the bad people, etc. There's so many possibilities :)

Have fun! :D

I just think that originality is key. And everyone who does that is just following a mold created by past authors, and they're afraid of restarting the whole mold.