M46 Plus Two . ... It still contains a few hundred stars within a span of 30 light-years or so. ... In this pretty starscape, the colorful, circular patch above and right of the center of M46 is the planetary nebula NGC 2438. ... NGC 2438 is estimated to be only 3,000 light-years distant, though, and moves at a different speed than M46 cluster members. Along with its fainter cohort, planetary nebula NGC 2438 is likely only by chance appearing near our line-of-sight to the young stars of M46. ...