NGC 6397 – a globular cluster

Today we look at NGC 6397 in our section Sydney Universe Watch and show you where to find this globular cluster.

Some notes on NGC 6397

Back in 1994, the Hubble telescope began searching NGC 6397 looking for red dwarf stars to find out if red dwarfs were common in the Milky Way.

(Click to Enlarge)

In 2003, it was found that there were 4 different types of stars found in the center of NGC 6397

1. Helium white dwarfs – these are faint blue stars foind in the center of the cluster. These stars have intereacted with nearby stars and prematurely  lost their outer layer. This has exposed the star’s hot blue core which gives the star it’s color.

2. Blue Stragglers – a hot bright young star which formed when two stars collided together, merging to form a new star.

3. Normal white dwarfs – Spread throughout the globular clusters, these are common stars who had their outer laers burned off through normal processes.

4.  Cataclysmic variables- these are where a normal star and a white dwarf pair together . The white dwarf then begins pulling material away from the normal star and eventually consumes the material.

In 2006, the Hubble begins to see faint stars in the globular cluster which turn out to be the faintesr stars ever seen in a globular cluster at that time.

~ by sydneystargazers on August 1, 2010.

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