Singing the Dogstar Blues by Alison Goodman
One girl, one alien, one time machine...the rest is history Seventeen-year-old Joss is a wild girl who can play a mean harmonica. A rebel with a famous mother and sperm-donor father, Joss is about to start a course in Time Travel at the University, much to the Board's disgust. When Mavkel -- the first alien to be allowed to attend a course at the University -- selects Joss to be his study partner, life changes completely. Overnight, Joss transforms from Black Sheep to VIP, attracting more attention than is comfortable -- she's met an assassin, confronted an anti-alien lobby and had her freewheeling lifestyle nipped in the bud by the high security which surrounds the Chorian. But Mavkel's health is in the balance and there's something stopping the bonding process between him and Joss. The key to the mystery seems to be the identity of Joss's father, which means a trip back to the petri dish where it all began...