ζ Coronae Borealis, Latinised as Zeta Coronae Borealis, is the

Bayer designation A Bayer designation is a stellar designation in which a specific star is identified by a Greek alphabet, Greek or Latin letter followed by the genitive case, genitive form of its parent constellation's Latin name. The original list of Bayer design ...

of a

double star In observational astronomy, a double star or visual double is a pair of stars that appear close to each other as viewed from Earth, especially with the aid of optical telescopes. This occurs because the pair either forms a binary star (i.e. a ...

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 first constellati ...

Corona Borealis Corona Borealis is a small constellation in the Northern Celestial Hemisphere. It is one of the 48 constellations listed by the 2nd-century astronomer Ptolemy, and remains one of the 88 modern constellations. Its brightest stars form a sem ...

. The two components are separated by six arc-seconds and share the same

Hipparcos ''Hipparcos'' was a scientific satellite of the European Space Agency (ESA), launched in 1989 and operated until 1993. It was the first space experiment devoted to precision astrometry, the accurate measurement of the positions and distances of ...

catalogue number and

Flamsteed designation A Flamsteed designation is a combination of a number and constellation name that uniquely identifies most naked eye stars in the 88 modern constellations, modern constellations visible from southern England. They are named after John Flamsteed, au ...

. Each of the two is also a spectroscopic multiple system, with a total of five stars in the group.

Nomenclature

ζ Coronae Borealis has the Flamsteed designation 7 Coronae Borealis and the Hipparcos catalogue number HIP 76669. As a double star, the brighter component is designated A (e.g. WDS J15394+3638 A) while the fainter of the two is designated B. The brighter star is also known as ζ² Coronae Borealis and the fainter as ζ¹ Coronae Borealis. Each of the pair has its own

Bright Star Catalogue The Bright Star Catalogue, also known as the Yale Catalogue of Bright Stars, Yale Bright Star Catalogue, or just YBS, is a star catalogue that lists all stars of stellar magnitude 6.5 or brighter, which is roughly every star visible to the na ...

and

Henry Draper Catalogue The ''Henry Draper Catalogue'' (HD) is an astronomical star catalogue published between 1918 and 1924, giving spectroscopic classifications for 225,300 stars; it was later expanded by the ''Henry Draper Extension'' (HDE), published between 192 ...

numbers: HR 5833 and 5834, and HD 139891 and 139892 for ζ¹ and ζ² respectively.

System

ζ¹ Coronae Borealis is a single-lined

spectroscopic binary A binary star or binary star system 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 as separate stars us ...

, with an orbital period of about 9.5 days. The nature of the companion is unknown. The brighter star, ζ² Coronae Borealis, is a spectroscopic triple system, consisting of three massive stars. The inner pair orbit in 1.7 days, while the outer pair orbit in 251 days.

References

{{DEFAULTSORT:Zeta Coronae Borealis Coronae Borealis, Zeta Corona Borealis Coronae Borealis, 07 076669 5833 4 139891 2 Durchmusterung objects Double stars Spectroscopic binaries Triple star systems B-type main-sequence stars