Here’s a lovely little image from the Hubble Space Telescope to brighten up the beginning of your week… this is the Necklace Nebula, a recently discovered planetary nebula in the constellation Sagitta, the Arrow.
Like all planetaries, this one is caused by a dying star throwing off its outer layers as it burns the last dregs of its nuclear fuel in its core.
But this nebula is a little more interesting.
The dying star has an extremely close companion with an orbital period of just one day. The companion star actually revolves inside the dying star, which has the effect of speeding up its rotational rate. The fast-spinning star ejects its material in a bright ring, which is unusual feature for a planetary. The ring is obvious in this HST image, as are bright clumps of denser and hotter gas in the ring’s plane.
In this image, you can see the two close stars unresolved at the centre of the nebula.
The planetary nebula is cataloged as PN G054.2-03.4. You can’t see it in a backyard scope… it’s too dim and far away.
But fear not… we’ll return again shortly to the constellation Sagitta to have a look at some brighter sights, including a small comet over the next week or two.