A star in the constellation Serpens appears to be staging a colorful demise. It’s surrounded itself with a cloud of gas and dust that glows bright red — the Red Square Nebula.
The star is known as MWC 922. And astronomers have been piecing together its story since the discovery of the nebula a decade and a half ago.
A study last year, for example, said the system probably consists of two stars. The main star is about 15 times the mass of the Sun. It’s passed the end of its “normal” lifetime, so it’s puffed up to giant proportions. It blows a thick “wind” into space. Its unseen companion helps sculpt that wind into two cones, which flow in opposite directions. We happen to view the system in profile, so we see the outlines of the cones as a bright “X.”
There’s also a thin disk of gas between the cones, and a thicker disk outside them — all glowing bright red.
If the main star really is as heavy as the study says, then its demise is about to get even more dramatic. The star will explode as a supernova. As debris rams into the material in the Red Square Nebula, the entire system will glow even brighter — sculpted into new and beautiful shapes not by a dying star, but by a dead one.
MWC 922 is in Serpens Cauda, the tail of the serpent. It’s about a third of the way up the southeastern sky at nightfall. The star is far too faint to see without a telescope, though — at least for now.
More about Serpens tomorrow.