Eta Boötis

η Boötis (Latinised to Eta Boötis) is the binary pair's Bayer designation; η Boötis A and B those of its two components. The designations of the two constituents of the double pair as WDS J13547+1824A and B and those of ''A's components - Aa and Ab'' - derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU). Consequently, the Chinese name for Eta Boötis itself is (, ). In the indigenous Australian Boorong (Wergaia) culture, this star is named Weetkurrk, ==Properties==

Eta Boötis is a suspected spectroscopic binary with a reported period of 494 days, but the companion was not confirmed through speckle interferometry. This measurement does not rule out a low mass stellar companion of spectral class M7. Eta Boötis presents as a subgiant that has begun the process of evolving from a main sequence star into a red giant. It has about 1.7 times the mass of the Sun and 2.66 times the Sun's radius. The estimated age of this star is about 2.7 billion years. Based on its spectra, it has a significant excess of elements heavier than helium. In fact the ratio of iron to hydrogen is considered close to the upper limit for dwarf stars in the galactic disk. Eta Boötis appears close to the prominent star Arcturus (Alpha Bootis) in Earth's sky, and Arcturus is in fact its closest stellar neighbor, as both stars are nearly identical in distance from the Sun. The two stars are about 3.24 light-years apart, and each would appear bright in the other's sky. Arcturus would appear as roughly magnitude -5.2 (about 120 times brighter than it appears from Earth, or close to twice the brightness of Venus) in the night sky of a hypothetical planet orbiting Eta Boötis, while Eta Boötis would appear at about magnitude −2.4 (absolute magnitude −2.41 at 0.99 parsec) in the sky of a hypothetical planet orbiting Arcturus, or over twice the brightness of Sirius in the night sky. ==See also==