EarthSky // Tonight // Brightest Stars By Bruce McClure Jan 27, 2009

Epsilon Lyrae: Famous ‘double-double’ star

Vega is the brightest star in the constellation Lyra the Harp. Near Vega, you’ll find Epsilon Lyrae, a rather faint star. Yet Epsilon Lyrae is famous to stargazers. Binoculars reveal that it is actually a double star – two stars in one – and a telescope shows that each component star is also a double. That makes Epsilon Lyrae a double-double or quadruple star.

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How to find it

From our mid-northern latitudes, this intriguing star in the constellation Lyra the Harp shines for all least part of the night all year round. Epsilon Lyrae graces the nighttime from dusk till dawn on summer nights, and is high overhead on autumn evenings. In winter, this star appears in the northwest sky after dusk, and then in the northeast sky before dawn. When spring arrives in March, Epsilon Lyrae rises before midnight, then shines for rest of the night.

In addition to the star’s nighttime prevalence, Epsilon Lyrae is wonderfully easy to find. That’s good news for the novice sky watcher! All you have to do is to find the super-brilliant star Vega, the brightest star in the famous Summer Triangle asterism. Epsilon Lyrae, though a fairly faint star, shines in close vicinity to this beacon guide star. The gap between Vega and Epsilon Lyrae only amounts to the width of your little finger at an arm length away.

Star With A Multiple Personality

So what’s so special about this rather faint star close to Vega? It’s a star with a multiple personality. Epsilon Lyrae lets you enjoy a firsthand view of a binary star – two stars orbiting a common center of mass. Best of all, you don’t even need a telescope to see this stellar couple. Ordinary binoculars work just fine. Aim your binoculars at Vega to spot two equally bright pinpoints of light right next to one another, nor far from Vega in your binocular field. Quite conveniently, Epsilon Lyrae and Vega easily fit within the same field of view!

That single point of light we see as Epsilon Lyrae is actually two stars waltzing around each other in space. People with exceptionally good eyestight can actually see both stars with the unaided eye on a clear, dark night. For the rest of us mortals, binoculars bring this binary star into view.

Epsilon Lyrae is so much more than an ordianry binary. Each component is in itself a binary star. Therefore, that point of light we see as a single star is really 4 stars in one, with one stellar pair circling around the other stellar pair in an intricate gravitational dance. However, a telescope is needed to see all 4 of Epsilon Lyrae’s stars.

Science

Although Vega and Epsilon Lyrae look like they’re close together in space, they really aren’t. These stars only reside along the same line of sight. Astronomers have determined that Vega is some 25 light-years, whereas Epsilon is over 6 times farther, at about 160 light-years away. The two stars of Epsilon Lyrae that you see with binoculars are thought to be 10,000 times the sun/Earth distance apart, and probably take at least a half a million years to revolve around each other. The component binaries visible through the telescope are much closer together, and are believed to circle each other in periods of about 1,000 years.

Epsilon Lyrae’s position is RA: 18h 44m 18.5s, dec: +39° 40′ 12.4″

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4 Responses to Epsilon Lyrae: Famous ‘double-double’ star

  1. hello
    my name is patrick,i am very fascinated about your article here,in fact i reearch some things about epsilon ,the word and meaning itself,and so it happends i came across this site…i am not an astronomer myself but curious about the whole subject.
    my question now is,as there is an image about the lyra the harp constellation,can you refer me to the constellation that makes out the starsystem epsilon lyrae only?
    that would maybe be quite helpful for me.
    thak you very much
    regards
    patrick

  2. Dafydd says:

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  3. Some interesting information on here. Slightly off topic but I am so excited !. I saw Cats The Musical for the first time and the music along with the dancing is unbelievable. It is definitely an emotional journey that all the audience gets involved with !. ‘Cats’ will make you laugh and smile and touch certain places in your heart. Everybody left the theater singing, delighted and uplifted. If you get a opportunity to go and see ‘Cats’ I really recommend it.

  4. Z says:

    ^ “Slightly” off topic?!

    I think there are actually 5+ stars in the system (5 confirmed and more suspected). The star between the two binary pairs is the 5th member. A very interesting system.

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