Nu1 Boötis

Nu¹ Boötis is an orange-hued star in the northern constellation of Boötes. Its name is a Bayer designation that is Latinized from ν¹ Boötis, and abbreviated Nu¹ Boo or ν¹ Boo. This star has an apparent visual magnitude of +5.02,^[2] which is bright enough to be faintly visible to the naked eye. Based upon an annual parallax shift of 3.35 mas as seen from Earth,^[1] it is located approximately 970 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.^[10] It is drifting closer to the Sun with a radial velocity of −11.1 km/s.^[4]

For other stars with this Bayer designation, see ν Boötis.

Nu¹ Boötis

ν1 (right) and ν2 Boötis in optical light
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Boötes
Right ascension	15h 30m 55.75060s[1]
Declination	+40° 49′ 58.9743″[1]
Apparent magnitude (V)	+5.02[2]
Characteristics
Spectral type	K4.5 IIIb Ba0.4[3]
U−B color index	+1.91[2]
B−V color index	+1.59[2]
Astrometry
Radial velocity (Rv)	−11.12±0.16[4] km/s
Proper motion (μ)	RA: +10.563 mas/yr[1] Dec.: −8.385 mas/yr[1]
Parallax (π)	3.3492±0.077 mas[1]
Distance	970 ± 20 ly (299 ± 7 pc)
Absolute magnitude (MV)	−2.22[5]
Details
Radius	99.8±4.26[6] R☉
Luminosity	2,054±163[6] L☉
Surface gravity (log g)	1.15±0.17[7] cgs
Temperature	3,917±27[7] K
Metallicity [Fe/H]	+0.00±0.06[7] dex
Rotational velocity (v sin i)	4.2[8] km/s
Other designations
ν1 Boo, ψ Her, 52 Boötis, BD+41°2609, FK5 573, GC 20866, HD 138481, HIP 75973, HR 5763, SAO 45580, PPM 54790[9]
Database references
SIMBAD	data

This is an evolved K-type giant star with a stellar classification of K4.5 IIIb Ba0.4.^[3] The 'Ba0.4' suffix notation indicates this is a weak barium star,^[11] 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.^[12] The giant component has 99.8 times the radius of the Sun. It is radiating 2,054^[6] times the Sun's luminosity from its enlarged photosphere at an effective temperature of about 3,917 K.^[7]

Ptolemy considered Nu Boötis to be shared by Hercules, and Bayer assigned it a designation in both constellations: Nu Boötis (ν Boo) and Psi Herculis (ψ Her). When the modern constellation boundaries were fixed in 1930, the latter designation dropped from use.^[13]