Lyra – the lyre

March 12, 2017

Astronomy

orph_02High in the summer sky you’ll find Lyra, the lyre, which is a small harp-like musical instrument. On some old-timey maps it is depicted as a eagle, or sometimes a vulture, with a small lyre in its mouth. Clearly this one was designed by an astronomy club committee.

Orpheus is the mythical guy who started it all. He was the best rock star of all time. His music was so good, he could literally charm rocks. Like if you threw rocks at him while he was playing, the rocks would just go around him. When his wife died he wrote a song so sad that the gods cried and told him he could have her back but then she immediately died again because greek myths are not allowed to turn out happy. He tried to make the best of it, you know, carry on, meet a new girl and all. But then he went to a party where a bunch of angry drunk feminists tore him into little pieces and threw his harp in the river. An eagle (some say vulture) fetched the instrument from the river and placed it in the sky where it turned into several giant glowing balls of nuclear fusion.

precession2Vega (Alpha Lyrae) is the bright star of the summer sky. It has always been a favorite for astronomers to study. Many astronomers say it is the most important star other than the sun. It’s only about 26 light years away which is next-door in galactic terms. It’s only a few hundred million years old, and it’s around 10,000 degrees. It’s basically our young hot neighbor. What’s not to like?

About 12,000 years ago Vega was the north star, so it was probably even more of a favorite back when we were chasing woolly mammoths around.

Another thing about Vega, it’s the star that Jodie Foster goes to in the movie Contact. Spoiler: that’s when we find out that aliens look like Jodie Foster’s dad. Billions of dollars and trillions of miles to find that out. So if aliens land in your back yard and come knocking on your door, don’t be surprised.

jodie

RR Lyrae is another famous star, at least to astronomers concerned with figuring out how close is close and how far is far. The star is a “standard candle” which means we feel pretty good about estimating how much light it’s actually cranking out. We compare that to how difficult it is to read by, and we thus know precisely how far away it must be. There are other stars that are like it and just to be extra confusing we call them all RR Lyrae stars. What we really mean is that they are “RR Lyrae-ish” stars.

harlow-shapleyWhen we find a standard candle in a cluster of stars we pretty much know the distance to the whole cluster. That’s what Harlow Shapley did when he figured out the shape of the Milky Way in 1920. He’s shown here holding some sort of precursor to the iPad. He used RR Lyrae stars to find the distance to the globular clusters, such as M56 in Lyra. The globulars turned out to be closer on one side of us, and farther away on the other, thus confidently removing us from the center of the Universe. Except Shapley confusedly thought RR Lyrae stars were Cepheid Variables, which seems rather silly now.

In those days the Universe was not known to contain galaxies so Shapley assumed the center of everything was just over the next hill in Sagittarius. Now days we think the center is everywhere. So that’s all cleared up.

Epsilon Lyrae is a famous double star. If your scope has enough resolution you’ll find that each of the two stars is itself a double star. So it’s technically a double-double star and that’s what a lot of folks call it. There’s one star to the naked eye (usually), and two stars in binoculars. You get four stars in a telescope unless your scope has some serious collimation issues. There are probably even more stars involved but you need warp drive to see those.

m057The Ring Nebula (M57) is an awesome example of a planetary nebula, which is the thrown-off outer layers from an aging dying star. In an amateur telescope it looks like a spooky ghostly Cheerio. It’s very easy to find because it’s half-way between two bright stars, gamma and beta, on the south end of the constellation Lyra. Just find one of the stars in the scope, and then swing back and forth between them and settle in the middle. In a telescope’s field of view it takes up about as much room as Jupiter does, so ramp up the magnification the way you would for a planet.

lyrWith a proper filter, part of the ring looks slightly green which reveals that it is rich with oxygen, that is to say “rich” depending on how well oxygen is doing on the stock exchange I guess.

Oxygen is actually rather plentiful in the Universe thanks to events like planetary nebulae. Older stars fabricate oxygen in their bellies then blast it out into the galaxy so that beings like us can come along later and breath it in. Just look around you at all human-kind has done. It’s all possible thanks to an elderly star passing gas.

Carpe Noctem.

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