Delta Boötis, Romanization of Greek, Latinized from δ Boötis, is a double star in the northern constellation of Boötes, forming the easternmost member of the constellation's kite-shaped Asterism (astronomy), asterism of brighter stars. Based upon parallax measurements, it is located at a distance of approximately from the Earth. This star is sometimes called Princeps , meaning ''prince'' or ''prime'' in Latin. The origin of this name is unclear, although it usually appears in an astrology, astrological context. The apparent visual magnitude of this star is 3.5, making it visible to the naked eye Bortle Dark-Sky Scale, even during a Full Moon. The magnitude 7.81 companion can be viewed in binoculars or a small telescope. In Chinese astronomy, Chinese, (), meaning ''Heavenly Market enclosure, Seven Excellencies'', refers to an asterism consisting of δ Boötis, 42 Herculis, Tau Herculis, τ Herculis, Phi Herculis, φ Herculis, Chi Herculis, χ Herculis, Nu1 Boötis, ν¹ Boötis and Mu Boötis, μ¹ Boötis. Consequently, the Chinese star names, Chinese name for δ Boötis itself is (, en, the Seventh Star of Seven Excellencies.)
AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 26 日
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Properties

This system consists of a pair of stars located in physical proximity to each other and sharing a similar motion through space, suggesting that they may form a binary star system. Based upon their angular separation and their distance, they have a projected separation of 3,800 Astronomical Units (AU). If they are gravitationally bound to each other, the orbital period of the system would be at least 120,000 years. The brighter member of the pair has a stellar classification of G8 III, indicating that it has exhausted the supply of hydrogen at its core and stellar evolution, evolved into a giant star. It now has a radius more than ten times the radius of the Sun. Compared to the Sun, this star appears deficient in elements other than hydrogen and helium—what astronomers term the star's metallicity. The outer envelope of this star has an effective temperature of 4,847 K, which is what gives it the characteristic yellow hue of a G-type star. The secondary component has a stellar classification of G0 V, which suggests it is a main sequence star that may be similar in physical properties to the Sun. The apparent visual magnitude of this star is 7.81, making it much less luminous than the primary component.

References

External links

HR 5681

CCDM J15156+3319

Image Delta Boötis
{{DEFAULTSORT:Delta Bootis G-type giants G-type main-sequence stars Binary stars Boötes Bayer objects, Bootis, Delta Durchmusterung objects Flamsteed objects, Bootis, 49 Henry Draper Catalogue objects, 135722 Hipparcos objects, 074666 Bright Star Catalogue objects, 5681