Your homeworld in Starbound is a planet you select as your new home. When you do so, a whole new aspect of gameplay opens up. Everything that makes a planet unique is at your command. Feel like changing the weather? Build a weather centre! Don't like the terrain? Terraform it! Every aspect of the planet is under your control. Once you're happy with it, start populating it with characters you've met in your travels and take care of them! They'll have needs and desires and won't hesitate to ask for your help if they require assistance.
Starbound begins with you fleeing your original homeworld in a space shuttle, just as it's destroyed by an unknown enemy.