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updated: Dec 28, 2013, 12:00 PM
By Chuck McPartlin
In case you haven't decked the halls for the holidays yet, here are some
astronomical decorations from the winter sky above Santa Barbara.
Let's start with some strings of twinkly lights. Our winter sky is full
of bright open clusters, gravitationally bound groups of young stars
that populate the spiral arms of our Milky Way Galaxy. Many of them were
catalogued by Charles Messier, a French astronomer and comet hunter.
The Double Cluster in Perseus, also known as NGC 869 and NGC 884, is
about 7,500 light years away, and contains tens of thousands of stars.
Messier 34 is a cluster of about 400 stars, about 1,500 light years
away in Perseus.
Messier 38 is in the constellation Auriga, the Charioteer, and a bit over
3,000 light years away.
Messier 52 is in Cassiopeia, somewhere betweenn 3,000 and 7,000 light
years away. Absorption of light by dust clouds between us and the cluster
complicates the distance determination.
Messier 103 is about 9,000 light years away in Cassiopeia.
Not all stars are in clusters. Let's add some big bright dangly
ornaments of individual stars.
Aldebaran is the red giant star marking the eye of Taurus, the Bull.
It's around 65 light years away, and is so big that if you placed it where
our Sun is, it would reach more than half way out to the planet Mercury, a
radius of about 19 million miles.
Even larger is Mirfak, a white supergiant star, the brightest star in
Perseus. It's about 500 light years away, and 60 times larger in diameter
than our Sun. That's a radius of about 26 million miles.
Destined for the bottom of our tree is Betelgeuse, a red supergiant in the
shoulder of Orion. Placed where our Sun is, this puppy would reach out to
the orbit of Jupiter. It's around 600 light years away, and is destined to
blow up in a spectacular core-collapse supernova sometime soon, at least in
astronomical terms. Its name is quite poetic, too, coming from a garbled
version of an Arabic phrase meaning "Armpit of the Giant".
And since we don't often see snow in Santa Barbara, how about a little
flocking, maybe a trillion solar masses worth?
The Andromeda Galaxy is the closest large galaxy to the Milky Way. It
contains about a trillion solar masses, and is the farthest object normally
visible with the unaided eye, at a distance of about 2.5 million light years.
High overhead, and in just the right place to top our tree, is an especially
beautiful cluster of stars - the Pleiades, or the Seven Sisters.
The Pleiades cluster is a bit over 400 light years away, and contains thousands
of stars. The Maori say that it used to be a single bright star, the brightest
in the sky. It was always bragging about how great it was, so the god Tane came
along with a big wooden club and broke it up into the cluster. That didn't solve
his problem, though, as the cluster stars immediately began chattering among
themselves about how much prettier they were now that there were more of them.
Whatever holidays you're celebrating, have happy ones!
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