8 Mar. 2011

 

Sh2-284, the little elephant nebula

 

NASA's Wide-field Infrared Survey Explorer (WISE) has produced this curious image of the Galactic star forming region Sh2-284, whose shape, given a little imagination, resembles a baby elephant, with head, eyes and nose on the left, looking to the left.
This complex, in the constellation of Monoceros, is located in one of the outer arms of the Milky Way, in the direction opposite to the centre of the galaxy. The huge mass of gas and dust has at its centre an open star cluster, called Dolidze 25, whose intense radiation has swept up the surrounding dusty interstellar medium, leaving a large "hole".
Where this medium was initially denser, the stellar winds were less effective, and in certain regions the original medium is seen as an elongated structure protruding into the central void (very evident that at 3 O'clock). In these sub-structures, a few light years long, the compression of the gas has triggered the formation of new stars, that have then acted as a screen against the radiation from Dolidze 25.
These are what were referred to as "Pillars of creation" when imaged for the first time in the Eagle nebula with the Hubble Space Telescope. As usual for the nebulae associated with open clusters, the fate of Sh2-284 is that it will become ever more eroded by the stars born within it, until eventually disappearing completely.

 

by Michele Ferrara & Marcel Clemens

credit: NASA/JPL-Caltech/UCLAy