The Night Sky: Constellation Lyra

Attached are two pictures I’ve taken of the night sky. One is a wide angle picture of the constellation Lyra and the other is a close-upof the Ring Nebula

Lyra constellation picture was taken with a 35mm camera lens and the Ring Nebula picture was taken through a telescope. The constellation Lyra can be found nearly straight up inthe sky after dark this time of year. Vega is the brightest star in the constellation Lyra and is the fifth brightest star in the sky. Vega’s brightness makes it easy to find Lyra. Give it a try on the next clear night.

Vega is 25 light years away, has a mass two times that ofour Sun, and is over 40 times brighter. But our Sun will shine 10 times longer than Vega. Vega will fuse all of the hydrogen in its core long before our Sundoes. When it runs out of hydrogen, about 400,000 years from now, Vega will swell into a red giant star and violently throw off half of its mass out into space. All that will remain of the once brilliant Vega will be a small white dwarf star about the size of the Earth. At that point nuclear fusion inside Vega will have stopped and it will slowly fade away.

Long ago another star in Lyra had already gone through this process, and the second picture is a telescope close-up of the result. The shell of gas the star ejected long ago is now known as the Ring Nebula. The Ring Nebula is classified as a planetary nebula because of its shape and appearance. It is two thousand light years away and one light year in diameter. (One light year equals about 6 trillion miles.)

The central white dwarf star can be seen in the picture, but it is very difficult to see visually in a telescope. This enriched nebulous star material of the Ring Nebula will spread out into space and some day seed new stars and planets. The Double-Double is the close pair of stars in the Lyra picture.

The Double-Double (DD) is officially known as Epsilon Lyra and is a quadruple star system 162 light years away. Two pairs of stars orbit around a common center of gravity. Separated by only two-tenths of a light, the two pairs take hundreds of thousands of years to orbit each other. One pair of stars in this quadruple system is separated by 5 times the distance from thesun to Neptune (140AU). It takes about 1,200 years for them to complete oneorbit. The other star pair takes only 800 years to orbit even though theirseparation appears similar as viewed from Earth. Imagine living on a hypothetical planet orbiting one of the four stars of the Double-Double! Clear Skies!