“It is all part of a grand cycle that turns over the course of billions of years”

A wondrous composite image of our nearest galactic neighbour, the Andromeda galaxy, as unveiled on the BBC’s Stargazing Live programme tonight. 

Combining an infrared view from ESA’s Herschel observatory with an X-ray view by the similarly orbiting XMM-Newton observatory, it shows at least five concentric rings of star-forming dust [infrared in orange] along with X-ray sources [in blue] where collapsed stars – white dwarfs, neutron stars and black holes – are located.  It’s a similar composite view to that taken of the Whirlpool Galaxy, Messier 51, in June 2009.

From the BBC’s science correspondent Jonathon Amos

The XMM-Newton portion of the image (dominated by the blue colour) shows hundreds of X-ray sources within Andromeda, many of them clustered around the centre where the stars are densest.

Some of the X-ray emission will be coming from locations where the gravity from aged stars, known as white dwarfs, is pulling gas from larger companion stars.

In these systems the white dwarfs may eventually grow massive enough to collapse catastrophically and explode as supernovas. Other X-rays will be coming from locations where long-dead, super-dense stars – known as neutron stars – and even black holes are also stealing material from nearby normal stars.

It is all part of a grand cycle that turns over the course of billions of years.

As stars explode they disperse gas and dust across the galaxy. The shockwaves from these explosions will also perturb this and other material, triggering the gravitational collapse of these clouds and the formation of yet more stars.

More on Herschel in the Slugger archive here.  And I’ll highlight this post.

Adds  ESA press release