And now, something a little different! 06.17.11

Star clusters fall into two main types: open clusters, which are fairly young, and globular clusters, which can be as old as the Milky Way itself. The older the cluster, the less elements heavier than hydrogen it contains. Open clusters tend to scatter and spread out over time.

So what’s the deal with open cluster NGC 6791? Out of the 2,000-some known clusters, it is different. At 13,000 light years away in the constellation Lyra, and with around 60,000 members, NGC 6791 has both old and new characteristics, the first of its kind. The large open star cluster is twice as enriched in heavy elements as our sun, which makes it about 8 billion years old, but has stars belonging to both types of clusters, red and very blue stars, and bright horizontal branch stars that are normally found in globular clusters.

     It’s an oddball that will keep the astronomers, like Imants Platais of Johns Hopkins University, busy for awhile.

A recent discovery in astronomy challenges knowledge of stars, 08.20.10

You may have read in the news lately about a fairly recent discovery in astronomy that is leaving astronomers questioning what they know about the life cycles and behavior of stars. An astronomer at Thronateeska Heritage Center says not to have worries about a recent discovery in our universe, though. Despite its enormous magnetic field, its safe distance away will cause no foreseeable problems in the near future for Earth.


An odd kind of neutron star called a “magnetar” because of its massive magnetic field is puzzling astronomers at the European Southern Observatory’s Very Large Telescope in Chile. It is located in the constellation Ara (the Altar), 16,000 light years away in a star cluster called Westerlund 1. This cluster is 3.5 to 5 million years old and should not have produced a “magnetar” because it is too young. Another problem is that the star that created this “magnetar” was far too large to have done what it did; it should have made a black hole out of its supernova remnant. The magnetic field that this “magnetar” has generated is about one million billion times stronger than that of Earth.


This strange behavior is causing a dilemma for astronomers. Because the giant collapsing star that created the “magnetar” did not behave as it should have, this might rewrite the book on stellar evolution of massive stars.


Discussions on this subject will be open to the public between planetarium shows at the Wetherbee Planetarium this Saturday, August 21^st. Call 229-432-6955 or visit http://heritagecenter.org for planetarium show times.