Wednesday 29 March 2017

The Intergalactic Wanderer

Globular clusters are among the most spectacular objects out there. Imagine these almost perfect spheres that consist of hundreds of thousands of stars! They usually accompany a parent galaxy, although the word parent is somewhat out of place because globular clusters are generally older than the galaxy around which they orbit. They're among the oldest objects in our universe and contain the oldest known stars. Life in such a place would be hard to find since any possible planet would experience severe tidal disturbances from the multitude of extremely close stars.

As I said, globulars are usually bound to a galaxy and have the same origin. But every now and then there's this oddball (literally in this case) that doesn't exactly follow the rules. NGC2419 not only lies almost exactly opposite to our galactic centre, it's also such a distant globular cluster, travelling at some 300.000 lightyears away from us, that scientists believed for a long time that it was a loner and not tied to our galaxy at all. Hence the nickname "Intergalactic Wanderer". Recent study changed that view somewhat and we now know that it does obey our Milky Way's gravitational pull, albeit with some reluctance, and that it makes one rotation every 3 billion years. That's a very long time, isn't it? 

From an observation point of view, it's a rather faint globular obviously because of its extreme distance, but it should be visible also in modest telescopes given a not too light-polluted sky. resolving stars in it is another question. Whereas most other globulars will happily resolve into an uncountable amount of individual stars, you'll have a run for your money with this one. A friend of mine stated that he's never been able to resolve it with his 24" telescope, not even at 400x. With my binoscope I did manage to see some individual stars at 504x, but for the rest it remained a greyish blob with some hints of structure. Yet, the peculiarity of this object does make it a worthwhile winter target. 


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