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 or Latin letter followed by the genitive form of its parent constellation's Latin name. The original list of Bayer designations contained 1,564 stars. ...

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 bi ...

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 ...

Corona Borealis. 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 of celestial obj ...

catalogue number and Flamsteed designation. 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 and Henry Draper Catalogue 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 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 ...

, 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