Chi Draconis (χ Dra, χ Draconis, Chi Draconis) is a magnitude 3.6

binary star A binary star is a system of two stars that are 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 separate stars, in wh ...

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 * D ...

. It also has the Flamsteed designation ''44 Draconis''. At a distance of 27 light years, it is one of the forty or so closest stars.

Binary system

χ Draconis is a

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 ...

which has been resolved using speckle interferometry. The primary is an F7

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. The spectral type of the companion cannot be determined directly with any accuracy, but is known to be between G8 and K2 and is assumed to be K0. The properties of the secondary suggest that it is also a main-sequence star. The separation of the two stars varies between about and during the

eccentric Eccentricity or eccentric may refer to: * Eccentricity (behavior), odd behavior on the part of a person, as opposed to being "normal" Mathematics, science and technology Mathematics * Off-center, in geometry * Eccentricity (graph theory) of a v ...

182-day orbit. The primary star has a mass fractionally higher than the Sun's, but is significantly larger and hotter resulting in it being 86% more luminous. Its age is estimated to be about five billion years. The secondary only has about three-quarters the mass of the Sun and is both cooler and smaller. It is only about 29% as luminous. It is calculated to be 2.13 magnitudes fainter than the primary, so it would be of sixth magnitude if visible alone.

Visual companions

Multiple star catalogues list faint widely-separated visible companion stars: a 12th-magnitude star and a 14th-magnitude star about from χ Draconis, but only about from each-other. Both have much smaller parallaxes than χ Draconis and are likely to be unrelated background objects.

References

External links

ARICNS

at SolStation.
nStars database entry
{{Stars of Draco Draco (constellation) Binary stars Draconis, Chi F-type main-sequence stars K-type main-sequence stars 089937 Draconis, 44 6927 170153 Durchmusterung objects 0713

Binary system

Visual companions

See also

References

External links