Nu1 Boötis (ν1 Boötis) is an orange-hued star in the northern constellation of Boötes. It has an apparent visual magnitude of +5.02, which indicates the star is faintly visible to the naked eye. Based upon an annual parallax shift of 3.89 mas as seen from Earth, it is located roughly 840 light years distant from the Sun. At that distance, the visual magnitude of the star is diminished by an extinction of 0.13 due to interstellar dust.
This is an evolved K-type giant star with a stellar classification of . The 'Ba0.4' suffix notation indicates this is a barium star, which means that the stellar atmosphere has been enhanced by s-process elements most likely provided by what is now an orbiting white dwarf companion. The giant component has times the radius of the Sun. It is radiating 1,626 times the Sun's luminosity from its enlarged photosphere at an effective temperature of about 3,917 K.
Ptolemy considered Nu1 Boötis to be shared by Hercules, and Bayer assigned it a designation in both constellations: Nu1 Boötis (ν1 Boo) and Psi1 Herculis (ψ1 Her). When the modern constellation boundaries were fixed in 1930, the latter designation dropped from use.[1]