Psi2 Draconis

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]
Distance930 ± 20 ly
(287 ± 7 pc)
Absolute magnitude (MV)−2.12±0.14[6]
Details[5]
Mass2.02 M☉
Radius14.70+0.64
−0.34[1] R☉
Luminosity448±13[1] L☉
Surface gravity (log g)2.32 cgs
Temperature6925+83
−152[1] K
Metallicity [Fe/H]−1.29 dex
Rotational velocity (v sin i)50[7] km/s
Age800 Myr
Other designations
ψ2 Dra, 34 Dra, BD+72° 818, FK5 3429, HD 164613, HIP 87728, HR 6725, SAO 8961[8]
Database references
SIMBADdata

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]

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]

  1. ^ a b c d e f g h i j k Cite error: The named reference dr2 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference Oja1983 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Gray2001 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Cowley_Bidelman_1979 was invoked but never defined (see the help page).
  5. ^ a b c d e Cite error: The named reference Casagrande2011 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Holmberg2009 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Danziger_Faber_1972 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Sinnott_Perryman_1997 was invoked but never defined (see the help page).