Double Double

A Dictionary of Astronomy | 1997 | 505 words | Copyright

Double Double The quadruple star Epsilon Lyrae. With binoculars, or even sharp eyesight, the star appears as a wide double of magnitudes 4.6 and 4.7 which form a genuine binary. Moderate-sized telescopes reveal that each star is itself double. The pair known as Epsilon¹ consists of an A4 dwarf and an F1 dwarf of magnitudes 5.0 and 6.1, orbiting each other in a period of about 1800 years; the Epsilon² pair consists of an A8 dwarf and an F0 dwarf, magnitudes 5.2 and 5.5, orbital period about 720 years.

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