1 Boötis

1 Boötis (also designated ν Boötis, Nu Boötis) is a binary star system located in the constellation Boötes. It is approximately 870 light-years from Earth. The primary component is a bright giant star of spectral type K4III, indicating it is an evolved star that has exhausted the hydrogen fuel in its core and has expanded significantly.

The star is characterized by its relatively cool surface temperature, giving it an orange hue. It is significantly more luminous than the Sun due to its large size. 1 Boötis is classified as a spectroscopic binary, meaning its binary nature is revealed through variations in its spectrum caused by the orbital motion of the two stars around a common center of mass. While the secondary component is not directly observed, its presence is inferred from the Doppler shifts in the spectrum of the primary star. The orbital period of the system is estimated to be quite long, spanning many years.

The apparent magnitude of 1 Boötis is approximately 5.04, making it faintly visible to the naked eye under dark skies. Its position in Boötes places it near other notable stars in the constellation, which is easily identified by its kite-like shape and the bright star Arcturus.