Would float in a bathtubNASA/ESA/G. Bacon (STScI)By Shannon HallA star’s heat goes deep. For the first time, we have spotted a “hot Jupiter” that has expanded thanks to its swelling host star – an observation that could settle a 15-year-old debate. Hot Jupiters – gas giant exoplanets that orbit scorchingly close to their stars – are inexplicably puffy....