How are newly discovered objects (stars, planets, galaxies...) named?

Question

When a new astronomical object (star, planet, galaxy, comet, etc.) is discovered, what is the official procedure to name it? Who decides about the name of it? Can they be changed in time?Extra question: How were the areas on the surface of the Moon and planet Mars named?

Answer 1

I'm pretty sure that it's the purview of the International Astronomical Union to name newly discovered astronomical objects.