I really like what you have painted and how you have placed the planet in space, I can not tell you that colors are good because I do not know the planet as you. But if it is not that color then you created a new planet, it is not bad at all either.
Certainly be used to painting something that you are seeing with your own eyes to go to paint something that may not be so, sometimes it is complicated, because the result may not be what it should be and you are not happy, if it is something that exists but you have not seen! (Trust in the media, news, social networks and other things that are not yourself is difficult). But if it is something that you want to create, you decide how perfect it is according to your wishes.
Your study must be great.
Greetings Matteo!
RE: Jupiter and Io (Detail) by Matthew Holden Bates