Nu2 Boötis

Nu² Boötis

File:Nu1 Bootis.jpg ν1 (right) and ν2 (left) Boötis in optical light
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Boötes
Right ascension	Template:RA
Declination	Template:DEC
Apparent magnitude (V)	5.02 (5.80 + 5.80)
Characteristics
Spectral type	A5 V
U−B Template:Engvar	+0.11
B−V Template:Engvar	+0.07
R−I Template:Engvar	0.04
Astrometry
Radial velocity (Rv)	Template:Val km/s
Proper motion (μ)	RA: −22.887 mas/yr Dec.: −12.041 mas/yr
Parallax (π)	7.3894±0.1816 mas
Distance	Template:Rnd ± Template:Rnd ly (Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)	−0.59
Orbit
Period (P)	Template:Val yr
Semi-major axis (a)	Template:Val″
Eccentricity (e)	Template:Val
Inclination (i)	Template:Val°
Longitude of the node (Ω)	Template:Val°
Periastron epoch (T)	Template:Val
Argument of periastron (ω) (secondary)	Template:Val°
Details
Mass	Template:Val Template:Solar mass
Radius	Template:Val Template:Solar radius
Luminosity	Template:Val Template:Solar luminosity
Temperature	Template:Val K
Rotational velocity (v sin i)	217 km/s
Metallicity [Fe/H]	{{{metal_fe2}}} dex
Other designations
Template:Odlist
Database references
SIMBAD	data
Data sources:
Hipparcos Catalogue, CCDM (2002), Bright Star Catalogue (5th rev. ed.)

Nu² Boötis is a white-hued binary star system in the northern constellation of Boötes. Its name is a Bayer designation that is Latinized from ν² Boötis, and abbreviated Nu² Boo or ν² Boo. This system is faintly visible to the naked eye as a point of light with a combined apparent visual magnitude of 5.02. Based upon an annual parallax shift of Template:Val as seen from the Earth, it is located approximately Template:Convert  light years from the Sun. The system is moving closer to the Sun with a radial velocity of −16.6 km/s.

This stellar pair have a nearly circular orbit with a period of nine years and a semimajor axis of 0.0615 arc seconds. They are both of visual magnitude 5.80 and display a similar spectrum, with the primary, component A, being an A-type main sequence star with a stellar classification of A5 V. This has been identified as an A-type shell star, suggesting there is a circumstellar disk of gas orbiting one or both stars. There are two other stars that appear close to the pair, termed C and D, but they are physically unrelated.

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.