Epsilon Lyrae

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-cm 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 years. Epsilon² consists of a magnitude 5.1 and 5.5 pair with an orbital period of 585 years. 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)
distance	162 light-years
position	R.A. 18h 44m 18.5s, Dec. +39° 40' 13"
other designations	SAO 67315, GSC 3122:3439, HIP 91926, B+39 3510

Related categories

• NOTABLE STARS
• VARIABLE STARS

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Encyclopedia of Alternative Energy & Sustainable Living
Encyclopedia of History

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