Our home galaxy, the Milky Way, gives birth to new stars at a leisurely rate — the equivalent of one Sun per year. But you wouldn’t think the rate was that low if you looked deep into Serpens Cauda — the tail of the serpent. Several stellar nurseries there are busily churning out baby stars — some of which are really big babies.
The nurseries all appear to belong to the Serpens Molecular Cloud. Its gas and dust are cold and dark. But a few million years ago, something rippled through the cloud. That caused knots of gas and dust to begin collapsing to form stars.
Today, that’s taking place mainly in three big clusters. They’re known as Serpens Main and South, and Westerhout 40. In all, they appear to contain at least 2,000 young stars or future stars — some of the objects are so young that they’re just now igniting the nuclear fires in their cores. And some aren’t even that far along — they’re dark knots that are the seeds of future stars.
Most of the stars in these clusters are small and faint. But a few are members of the most impressive classes of stars. One of them, in the center of Westerhout 40, is especially hot and bright. It’s blowing away the nearby gas and dust. That will shut down the birth of new stars close by, but perhaps trigger the birth of stars farther away. And the star has blown a colorful bubble around itself that resembles a butterfly — the result of starbirth in the serpent.
More about Serpens tomorrow.