Zeta Boötis, Latinized from ζ Boötis, is a binary star system in the constellation of Boötes. They have the

Flamsteed designation A Flamsteed designation is a combination of a number and constellation name that uniquely identifies most naked eye stars in the modern constellations visible from southern England. They are named for John Flamsteed who first used them while co ...

30 Boötis; ''Zeta Boötis'' is the Bayer designation. This system is visible to the naked eye with a combined

apparent magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's ...

of +3.78. The individual magnitudes differ slightly, with component A having a magnitude of 4.46 and component B at the slightly dimmer magnitude 4.55. It is located at a distance of approximately 180 light years from the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

based on parallax, but is drifting closer with a radial velocity of −9 km/s. The duplicity of this star was discovered by English astronomer

William Herschel Frederick William Herschel (; german: Friedrich Wilhelm Herschel; 15 November 1738 – 25 August 1822) was a German-born British astronomer and composer. He frequently collaborated with his younger sister and fellow astronomer Caroline ...

in 1796, and their changing positions have been tracked from 1823 onward. They complete an orbit roughly every . The orbit of this pair has a very high eccentricity of 0.9977, bringing the stars within 0.3 AU at their closest approach. The next close approach will occur during August 2023. In 1976, T. W. Edwards found a stellar classification of A2III for both components, suggesting they may be

evolved Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...

A-type

giant stars A giant star is a star with substantially larger radius and luminosity than a main-sequence (or ''dwarf'') star of the same surface temperature.Giant star, entry in ''Astronomy Encyclopedia'', ed. Patrick Moore, New York: Oxford University Pre ...

. Helmut A. Abt reported a class of A2V in 1981, which matches an

A-type main-sequence star An A-type main-sequence star (A V) or A dwarf star is a main-sequence (hydrogen-burning) star of spectral type A and luminosity class V (five). These stars have spectra defined by strong hydrogen Balmer absorption lines. They measure between ...

. Abt and Nidia Morrell updated the classification to A1V in 1995. Considering the extreme nature of their orbit, it is unlikely that any companion exoplanets could have stable orbits around either star.

Gallery

Image:zboo lucky image 1pc.png, Zeta Bootis imaged with the Nordic Optical Telescope on 13 May 2000 using the

lucky imaging Lucky imaging (also called lucky exposures) is one form of speckle imaging used for astrophotography. Speckle imaging techniques use a high-speed camera with exposure times short enough (100 ms or less) so that the changes in the Earth's a ...

method. (The

Airy disc In optics, the Airy disk (or Airy disc) and Airy pattern are descriptions of the best- focused spot of light that a perfect lens with a circular aperture can make, limited by the diffraction of light. The Airy disk is of importance in physics, ...

s around the stars is diffraction from the 2.56m telescope aperture.) Image:Zeta bootis short exposure.png, Typical short-exposure image of a binary star, as seen using

speckle imaging Speckle imaging describes a range of high-resolution astronomical imaging techniques based on the analysis of large numbers of short exposures that freeze the variation of atmospheric turbulence. They can be divided into the shift-and-add ("'' ...

through the Earth's atmosphere.

References

External links

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HR 5477

Image Zeta Boötis

CCDM J14411+1344
{{DEFAULTSORT:Zeta Bootis A-type giants A-type main-sequence stars Binary stars Boötes Bootis, Zeta BD+14 2770 Bootis, 30 129246 7 071795 5478 Astronomical objects discovered in 1796