The dust and wind storm on the L dwarf W1906+40 rotates around the cool star every nine hours and is large enough to hold three Earths. L-dwarfs mark the boundary between real stars and “failed stars” only the most massive L dwarfs fuse hydrogen atoms and generate energy like our sun. Most L dwarfs known are brown dwarfs, also known as “failed stars,” because they never sustain atomic fusion. (JPL/NASA-Caltech)