To create a new star press the add button and then press "change star type" to be prompted with choices of star color. Red, Green, Blue, Yellow, Random and Random non-green (ftw?).
The non-green thing made me wonder if there was something special here. Looked it up, and come to find out that there are no green stars in the real world. Any that come close to green are perceived as white (like Sol, our sun). Here's a link to a good article about it.