Double-tailed star nursery

The Elephant's Trunk Nebula, taken by NASA's Spitzer Space Telescope. NASA/JPL-Caltech/W. Reach (SSC/Caltech)

Thanks to some spectacular pictures like the one above, we now know that stars are formed in ‘molecular clouds’. These are spectacularly beautiful and immense clouds of gas and dust, also referred to as ‘stellar nurseries’.

Although these molecular clouds can take many different shapes, astronomers were amazed to find one with a double X-ray tail stretching more than 200,000 light years. Part of this tail is located in the ESO 137-001 galaxy, (219 million light years from the Milky Way), but it extends past that galaxy’s borders, a hitherto unknown possibility. It had been thought that star formation had to be limited to the interior of galaxies.

Photo of double-tailed glass cloud, courtesy of the Chandra X-Ray Observatory.

Michigan State University astronomer Megan Donahue led the international team of astronomers who discovered this anomaly. The first tail had been seen three years ago, but the discovery of the second tail, made by the Chandra X-ray Observatory, surprised everyone.

According to Donahue:

The double tail is very cool – that is, interesting – and ridiculously hard to explain. It could be two different sources of gas or something to do with magnetic fields. We just don’t know.