Omicron Draconis (Latinised as ο Draconis, abbreviated to ο Dra) is a

giant star A giant star is a star with substantially larger radius and luminosity than a main sequence, main-sequence (or ''dwarf'') star of the same effective temperature, surface temperature.Giant star, entry in ''Astronomy Encyclopedia'', ed. Patrick Moo ...

in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

Draco Draco is the Latin word for serpent or dragon. Draco or Drako may also refer to: People * Draco (lawgiver) (from Greek: Δράκων; 7th century BC), the first lawgiver of ancient Athens, Greece, from whom the term ''draconian'' is derived * ...

located 322.93

light year A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

s from the Earth. Its path in the night sky is

circumpolar Circumpolar may refer to: * Antarctic region ** Antarctic Circle ** the Antarctic Circumpolar Current ** Subantarctic ** List of Antarctic and subantarctic islands ** Antarctic Convergence ** Antarctic Circumpolar Wave ** Antarctic Ocean * Arctic ...

for latitudes greater than 31^o north, meaning the star never rises or sets when viewed in the night sky. OmicronDraLightCurve

Omicron Draconis can be considered the north

pole star A pole star or polar star is a star, preferably bright, nearly aligned with the axis of a rotating astronomical body. Currently, Earth's pole stars are Polaris (Alpha Ursae Minoris), a bright magnitude-2 star aligned approximately with its ...

Mercury Mercury commonly refers to: * Mercury (planet), the nearest planet to the Sun * Mercury (element), a metallic chemical element with the symbol Hg * Mercury (mythology), a Roman god Mercury or The Mercury may also refer to: Companies * Merc ...

, as it is the closest star to Mercury's north

celestial pole The north and south celestial poles are the two points in the sky where Earth's rotation around a fixed axis, axis of rotation, indefinitely extended, intersects the celestial sphere. The north and south celestial poles appear permanently dire ...

. This is a single-lined

spectroscopic binary A binary star is a system of two star, stars that are gravity, gravitationally bound to and in orbit around each other. Binary stars in the night sky that are seen as a single object to the naked eye are often resolved using a telescope as separa ...

system, but the secondary has been detected using

interferometry Interferometry is a technique which uses the ''interference'' of superimposed waves to extract information. Interferometry typically uses electromagnetic waves and is an important investigative technique in the fields of astronomy, fiber opt ...

. It is an

RS Canum Venaticorum variable An RS Canum Venaticorum variable is a type of variable star. The variable type consists of close binary stars having active chromospheres which can cause large stellar spots. These spots are believed to cause variations in their observed luminosi ...

system with eclipses. The total amplitude of variation is only a few hundredths of a magnitude. The secondary star is similar to the Sun, presumably a

main sequence In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Her ...

star, while the primary is a

25 times larger than the Sun and two hundred times more luminous.

References

External links

* 2004. Starry Night Pro, Version 5.8.4.

Imaginova Imaginova Corporation is a U.S. digital commerce company based in Watsonville, California. The company, which was started in 1999 as "Space.com" by CNN business anchor Lou Dobbs, later became known as Space Holdings Corp. Dan Stone became President ...

. . www.starrynight.com {{DEFAULTSORT:Omicron Draconis Draconis, Omicron Draco (constellation) G-type giants RS Canum Venaticorum variables Eclipsing binaries Draconis, 47 092512 7125 175306 Durchmusterung objects