Lost Stars — Lisa Selin Davis

Before her older sister, Ginny, died, Carrie was a science nerd, obsessively tracking her beloved Vira comet. But now that Ginny is gone, sixteen-year-old Carrie finds herself within the orbit of Ginny's friends, a close-knit group of seniors who skip school, obsess over bands (not science), and party hard.

Fed up with Carrie's behavior, her father enrolls her in a summer work camp at a local state park. Carrie actually likes the days spent in nature. And when she meets Dean, a guy who likes the real Carrie -- astrophysics obsessions and all -- she starts to get to the heart of who she is and who she wants to be.