Nu2 Coronae Borealis

Nu² Coronae Borealis is a solitary,^[11] orange-hued star located in the northern constellation of Corona Borealis. It is faintly visible to the naked eye, having an apparent visual magnitude of +5.4.^[2] Based upon an annual parallax shift of 5.72 mas, it is located roughly 571 light years from the Sun. At that distance, the visual magnitude is diminished by an extinction of 0.1 due to interstellar dust.^[12]

For other stars with this Bayer designation, see ν Coronae Borealis.

ν² Coronae Borealis

ν2 Coronae Borealis (lower red star) in optical light
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Corona Borealis
Right ascension	16h 22m 29.21832s[1]
Declination	+33° 42′ 12.5247″[1]
Apparent magnitude (V)	+5.396[2]
Characteristics
Evolutionary stage	RGB[3][1]
Spectral type	K5 III[4]
U−B color index	+1.787[2]
B−V color index	+1.525[2]
Astrometry
Radial velocity (Rv)	−41.1±0.2[5] km/s
Proper motion (μ)	RA: −5.537[1] mas/yr Dec.: +49.931[1] mas/yr
Parallax (π)	5.7163±0.0624 mas[1]
Distance	571 ± 6 ly (175 ± 2 pc)
Absolute magnitude (MV)	−0.78[6]
Details
Mass	1.1[7] M☉
Radius	64[1] R☉
Luminosity	880[1] L☉
Surface gravity (log g)	1.76[8] cgs
Temperature	3,940[8] K
Metallicity [Fe/H]	−0.16[8] dex
Rotational velocity (v sin i)	3.1[9] km/s
Other designations
ν2 Coronae Borealis, 21 CrB, BD+34 2774, HD 147767, HIP 80214, HR 6108, SAO 65259[10]
Database references
SIMBAD	data

This is an evolved red giant star with a stellar classification of K5 III.^[4] Nu² Coronae Borealis is 64 times bigger than the Sun, radiating 880 times the Sun's luminosity from its photosphere at an effective temperature of 3,940 K.

The star ν¹ Coronae Borealis lies 6′ borth of ν². ν¹ is also a red giant with almost the same apparent magnitude, but is a more luminous asymptotic giant branch star.^[13]