Bubbles and Arcs in NGC 2359
Explanation : What caused the bubbles and arcs in NGC 2359? The main suspect is the Wolf-Rayet star in the center of one of the bubbles - visible slightly below and to the right of the center of the above photograph . Most Wolf-Rayet stars are known to be massive, highly luminous stars that continually cast off material in a stellar wind - which commonly form bubbles in the interstellar medium . But the unusual structure of the NGC 2359 arcs indicate something more complex is going on. Is the star moving supersonically ? Is there another energetic star in the vicinity? Future observations may give more pieces to this picturesque puzzle.