... The hot star system known as MWC 922 , however, appears to be embedded in a nebula with just such a shape. ... A leading progenitor hypothesis for the square nebula is that the central star or stars somehow expelled cones of gas during a late developmental stage . ... Researchers speculate that the cones viewed from another angle would appear similar to the gigantic rings of supernova 1987A , possibly indicating that a star in MWC 922 might one day itself explode in a similar supernova . ...