Hubble Studies Generations Of Star Formation In Neighbouring Galaxy

The image illustrates a perfect case of so-called sequential star formation in a nearby galaxy - new starbirth triggered by old massive stars. The sequence begins with a cluster of stars outside the top of the Hubble image which led to the birth of the collection of blue- and white-coloured stars near the left of this new Hubble image. These stars are among the most massive stars known anywhere in the Universe. The region around the hot stars is relatively clear of gas, because the stellar winds and radiation from the stars have pushed the gas away. When this gas collides with surrounding material, it is compressed and can collapse under its own gravity and start to form new stars. This chain of consecutive star birth episodes has been seen in more distant galaxies, but it is shown very clearly in this Hubble image.

Farther to the right of the image, along the top edge, are several smaller dark clouds, or globules, of interstellar dust with odd and intriguing shapes. They are seen silhouetted against the glowing interstellar gas. Several of these dark globules are bright-rimmed because they are illuminated and are being evaporated by radiation from neighbouring hot stars. A generation of new stars is now being born inside these globules.

In N11 altogether three generations of stars can be found. 'Grandmother' stars (outside the top of the Hubble image) that have carved a large superbubble, leading to the birth of the cluster of massive blue-white 'mother' stars seen near the top of this image. These in turn gives birth to new star 'babies' inside the dark globules.

This image was taken with Hubble's Wide Field Planetary Camera 2 using filters that isolate light emitted by oxygen (a 1200 seconds exposure) and hydrogen gas (a 1000 seconds exposure). The science team, led by astronomers You-Hua Chu (University of Illinois) and Yäel Nazé (Universite de Liège, Belgium) are comparing these images of N11B, taken in 1999, with similar regions elsewhere in the LMC. This colour rendition was co-produced and is being co-released by the Hubble European Space Agency Information Centre and the Hubble Heritage Team (STScI).