All work and no public meltdowns make Selena a dull girl. The Disney vet has dated – and, OMG, split from – Justin Bieber and released three LPs, all while remaining pop’s most ho-hum double threat. Stars Dance is her first album without her band, the Scene, and the first to feature orgasmic moans – see “Birthday,” featuring 16 seconds of what sure sounds like simulated sex. But though she nods at Rihanna-style slither and Britney-esque grind, this is the sound of Gomez gliding gracefully into adulthood. Her producers finally give her tighter tunes: “Slow Down” is ripe for remixing, and “Forget Forever” is a skittering tear-jerker worthy of the most-blogged breakup of 2013.