Friday, November 22, 2019

Find the Beehive Cluster

Find the Beehive Cluster Cancer: Home of the Beehive Cluster Stargazing is part observation and part planning. No matter what time of year it is, you always have something cool to look at or you are planning out your future observations. Amateurs are always plotting their next conquest of a difficult-to-spot nebula or the first view of an old favorite star cluster. Take the Beehive Cluster, for example. Its in the constellation  Cancer, the Crab, which is a zodiac constellation that lies along  the  ecliptic, which is  the apparent path of the  Sun  across the sky throughout the year.  This means that Cancer is  visible for most observers in both the northern and southern hemispheres in the evening sky from late winter from about January through May. Then it disappears in the glare of the Sun for a few months before showing up in the early morning sky beginning in September.   Beehive Specs The Beehive is a little star cluster with the formal Latin name Praesepe, which means the manger. Its just barely a naked-eye object, and looks like a fluffy little cloud. You need a really good dark-sky site and reasonably low humidity to see it without using binoculars. Any good pair of 7Ãâ€"50 or 10Ãâ€"50 binoculars will work, and will show you a dozen or two stars in the cluster. When you look at the Beehive, you see stars that are about 600 light-years away from us.   There are about a thousand stars in the Beehive, some similar to the Sun. Many are red giants and white dwarfs, which are older than the rest of the stars in the cluster. The cluster itself is about 600 million years old. One of the interesting things about the Beehive is that it has very few massive, hot, bright stars. We know that the brightest, hottest and most massive stars usually last anywhere from ten to several hundred million years before they explode as supernovae. Since the stars we DO see in the cluster are older than this, either it lost all its massive members already, or perhaps it didnt start with many (or any). Open Clusters Open clusters are found throughout our galaxy. They usually contain up to a few thousand stars that were all born in the same cloud of gas and dust, which makes most of the stars in a given cluster roughly the same age. The stars in an open cluster are mutually gravitationally attracted to  other when they first form, but as they travel through the galaxy, that attraction can be  disrupted by passing stars and clusters. Eventually, an open clusters stars move so far apart that it  disintegrates and its stars are scattered to the galaxy. There are several known moving associations of stars that used to be open clusters. These stars are moving at roughly the same velocity but are not gravitationally bound in any way. Eventually they, too, will wander on their own paths through  the galaxy. The best examples of other open clusters are the Pleiades and the Hyades, in the constellation Taurus.

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