Epsilon Lyrae is the fifth brightest star in the constellation Lyra and one of the most famous multiple stars in the sky: a naked-eye double (on a very clear, moonless night) that a 6-centimeter telescope with high magnification shows to be a quadruple system made up of two pairs of stars; it is commonly known as the Double Double.
Epsilon1 consists of two stars, of magnitude 4.7 and 6.2 magnitude, that orbit about their center of gravity every 1,200 yr. Epsilon2 consists of a magnitude 5.1 and 5.5 pair with an orbital period of 585 yr. In addition Epsilon1 and Epsilon2 orbit around each other in a huge orbit, with a separation of 0.16 light-year and a period measured in hundreds of thousands of years.
|visual magnitude||4.67 (Eps1), 4.59 (Eps2)|
|absolute magnitude||1.18 (Eps1), 1.10 (Eps2)|
|spectral type||F1V (Eps1), A8V (Eps2)|
|position||RA 18h 44m 18.5s,
Dec +39° 40' 13"
|other designations||SAO 67315, GSC 3122:3439,
HIP 91926, B+39 3510