Psi2 Draconis

Psi² Draconis is a solitary^[9] giant star in the northern circumpolar constellation of Draco, also designated 34 Draconis. It lies just over a degree east of the brighter Psi¹ Draconis.^[10] Psi² Draconis has a yellow-white hue and is dimly visible to the naked eye with an apparent visual magnitude of 5.45.^[2] It is located at a distance of 940 light-years (287 parsecs) from the Sun based on parallax, but is drifting closer with a radial velocity of −2 km/s.^[5]

For other stars with this Bayer designation, see ψ Draconis.

Psi² Draconis

Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Draco
Right ascension	17h 55m 11.15296s[1]
Declination	+72° 00′ 18.4470″[1]
Apparent magnitude (V)	5.45[2]
Characteristics
Spectral type	F2 III+[3] or F3 II-III[4]
U−B color index	+0.15[2]
B−V color index	+0.30[2]
Astrometry
Radial velocity (Rv)	−2.0[5] km/s
Proper motion (μ)	RA: +8.545[1] mas/yr Dec.: −2.133[1] mas/yr
Parallax (π)	3.4888±0.0832 mas[1]
Distance	930 ± 20 ly (287 ± 7 pc)
Absolute magnitude (MV)	−2.12±0.14[6]
Details[5]
Mass	2.02 M☉
Radius	14.70+0.64 −0.34[1] R☉
Luminosity	448±13[1] L☉
Surface gravity (log g)	2.32 cgs
Temperature	6925+83 −152[1] K
Metallicity [Fe/H]	−1.29 dex
Rotational velocity (v sin i)	50[7] km/s
Age	800 Myr
Other designations
ψ2 Dra, 34 Dra, BD+72°818, FK5 3429, HD 164613, HIP 87728, HR 6725, SAO 8961[8]
Database references
SIMBAD	data

According to R. O. Gray and associates (2001), the stellar classification of Psi² Draconis is F2III+;^[3] a star that has used up its core hydrogen, cooled, and expanded away from the main sequence. A. P. Cowley and W. P. Bidelman (1979) found a similar class of F3 II-III, with the comment that the spectrum showed "many weak lines".^[4] Based on the abundance of iron, the metallicity of this star is much lower than in the Sun. It is about 800^[5] million years old and is spinning with a projected rotational velocity of 50 km/s.^[7] The star has double^[5] the mass of the Sun but has expanded to 15^[1] times the Sun's radius. It is radiating 448^[1] times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 6,925 K.^[1]