Astronomy Picture of the Day

Explanation: Beautiful emission nebula NGC 6164was created by a rare, hot, luminousO-typestar, some 40 times as massive as the Sun.Seen at the center of the cosmic cloud, the star is a mere3 to 4 million years old.In another three to four million years the massive star will end itslife in a supernova explosion.Spanning around 4 light-years,the nebula itselfhas a bipolar symmetry.That makes it similar in appearance to more common and familiarplanetary nebulae- the gaseous shroudssurrounding dying sun-like stars.Also like many planetary nebulae, NGC 6164 has been found to havean extensive,faint halo,revealed in this deep image of the region.Expanding into the surroundinginterstellar medium,the material in thehalo is likely from an earlier active phase of the O star.This gorgeous telescopic viewis a composite of extensive narrow-band image data,highlighting glowing atomic hydrogen gas in red and oxygen in greenish hues,with broad-band data for the surrounding starfield.Also known as theDragon's Egg nebula,NGC 6164 is 4,200 light-years away in the right-angled southern constellationof Norma.