A Neptune-like exoplanet orbits an Earth-sized white dwarf star called WD J091405.30+191412.25 (WD J0914 for short) once every 10 days, leaving a comet-like tail of gas comprised of hydrogen, oxygen and sulfur, according to a new research led by University of Warwick astronomers. This illustration shows the white dwarf WD J0914 and its Neptune-like exoplanet. Image credit: M. Kornmesser / ESO. Stars like our Sun burn hydrogen in their cores for most...