# Psi2 Draconis

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Star in the constellation Draco

For other stars with this Bayer designation, see [ψ Draconis](/source/Psi_Draconis).

ψ2 Draconis Location of ψ2 Draconis (circled in red) 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

**Psi2 Draconis** is a solitary[9] [giant star](/source/Giant_star) in the northern [circumpolar constellation](/source/Circumpolar_constellation) of [Draco](/source/Draco_(constellation)), also designated **34 Draconis**. It lies just over a degree east of the brighter [Psi1 Draconis](/source/Psi1_Draconis).[10] Psi2 Draconis has a yellow-white hue and is dimly visible to the naked eye with an [apparent visual magnitude](/source/Apparent_visual_magnitude) of 5.45.[2] It is located at a distance of 940 light-years (287 parsecs) from the [Sun](/source/Sun) based on [parallax](/source/Stellar_parallax), but is drifting closer with a [radial velocity](/source/Radial_velocity) of −2 km/s.[5]

According to R. O. Gray and associates (2001), the [stellar classification](/source/Stellar_classification) of Psi2 Draconis is F2III+;[3] a star that has used up its core [hydrogen](/source/Hydrogen), cooled, and expanded away from the [main sequence](/source/Main_sequence). [A. P. Cowley](/source/Anne_Cowley) and [W. P. Bidelman](/source/William_P._Bidelman) (1979) found a similar class of F3 II-III, with the comment that the [spectrum](/source/Stellar_spectrum) showed "many weak [lines](/source/Absorption_line)".[4] Based on the abundance of iron, the [metallicity](/source/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](/source/Projected_rotational_velocity) of 50 km/s.[7] The star has double[5] the [mass of the Sun](/source/Mass_of_the_Sun) but has expanded to 15[1] times the [Sun's radius](/source/Sun's_radius). It is radiating 448[1] times the [luminosity of the Sun](/source/Luminosity_of_the_Sun) from its enlarged [photosphere](/source/Photosphere) at an [effective temperature](/source/Effective_temperature) of 6,925 K.[1]

## References

1. ^ [***a***](#cite_ref-dr2_1-0) [***b***](#cite_ref-dr2_1-1) [***c***](#cite_ref-dr2_1-2) [***d***](#cite_ref-dr2_1-3) [***e***](#cite_ref-dr2_1-4) [***f***](#cite_ref-dr2_1-5) [***g***](#cite_ref-dr2_1-6) [***h***](#cite_ref-dr2_1-7) [***i***](#cite_ref-dr2_1-8) [***j***](#cite_ref-dr2_1-9) [***k***](#cite_ref-dr2_1-10) [Brown, A. G. A.](/source/Anthony_Brown_(scientist)); et al. ([Gaia collaboration](/source/Data_Processing_and_Analysis_Consortium)) (August 2018). ["*Gaia* Data Release 2: Summary of the contents and survey properties"](https://doi.org/10.1051%2F0004-6361%2F201833051). *[Astronomy & Astrophysics](/source/Astronomy_%26_Astrophysics)*. **616**. A1. [arXiv](/source/ArXiv_(identifier)):[1804.09365](https://arxiv.org/abs/1804.09365). [Bibcode](/source/Bibcode_(identifier)):[2018A&A...616A...1G](https://ui.adsabs.harvard.edu/abs/2018A&A...616A...1G). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/201833051](https://doi.org/10.1051%2F0004-6361%2F201833051). [Gaia DR2 record for this source](https://vizier.u-strasbg.fr/viz-bin/VizieR-S?Gaia%20DR2%201639295390892588288) at [VizieR](/source/VizieR).

1. ^ [***a***](#cite_ref-Oja1983_2-0) [***b***](#cite_ref-Oja1983_2-1) [***c***](#cite_ref-Oja1983_2-2) [***d***](#cite_ref-Oja1983_2-3) Oja, T. (April 1983), "UBV photometry of FK4 and FK4 supplement stars", *Astronomy and Astrophysics Supplement Series*, **52**: 1311–34, [Bibcode](/source/Bibcode_(identifier)):[1983A&AS...52..131O](https://ui.adsabs.harvard.edu/abs/1983A&AS...52..131O).

1. ^ [***a***](#cite_ref-Gray2001_3-0) [***b***](#cite_ref-Gray2001_3-1) Gray, R. O.; et al. (April 2001), "The Physical Basis of Luminosity Classification in the Late A-, F-, and Early G-Type Stars. I. Precise Spectral Types for 372 Stars", *The Astronomical Journal*, **121** (4): 2148–2158, [Bibcode](/source/Bibcode_(identifier)):[2001AJ....121.2148G](https://ui.adsabs.harvard.edu/abs/2001AJ....121.2148G), [doi](/source/Doi_(identifier)):[10.1086/319956](https://doi.org/10.1086%2F319956).

1. ^ [***a***](#cite_ref-Cowley_Bidelman_1979_4-0) [***b***](#cite_ref-Cowley_Bidelman_1979_4-1) [Cowley, A. P.](/source/Anne_Cowley); Bidelman, W. P. (February 1979), "MK spectral types for some F and G stars", *Publications of the Astronomical Society of the Pacific*, **91**: 83–86, [Bibcode](/source/Bibcode_(identifier)):[1979PASP...91...83C](https://ui.adsabs.harvard.edu/abs/1979PASP...91...83C), [doi](/source/Doi_(identifier)):[10.1086/130446](https://doi.org/10.1086%2F130446).

1. ^ [***a***](#cite_ref-Casagrande2011_5-0) [***b***](#cite_ref-Casagrande2011_5-1) [***c***](#cite_ref-Casagrande2011_5-2) [***d***](#cite_ref-Casagrande2011_5-3) [***e***](#cite_ref-Casagrande2011_5-4) Casagrande, L.; et al. (2011), "New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey", *Astronomy & Astrophysics*, **530** (A138): 21, [arXiv](/source/ArXiv_(identifier)):[1103.4651](https://arxiv.org/abs/1103.4651), [Bibcode](/source/Bibcode_(identifier)):[2011A&A...530A.138C](https://ui.adsabs.harvard.edu/abs/2011A&A...530A.138C), [doi](/source/Doi_(identifier)):[10.1051/0004-6361/201016276](https://doi.org/10.1051%2F0004-6361%2F201016276), [S2CID](/source/S2CID_(identifier)) [56118016](https://api.semanticscholar.org/CorpusID:56118016).

1. **[^](#cite_ref-Holmberg2009_6-0)** Holmberg, J.; et al. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", *Astronomy and Astrophysics*, **501** (3): 941–947, [arXiv](/source/ArXiv_(identifier)):[0811.3982](https://arxiv.org/abs/0811.3982), [Bibcode](/source/Bibcode_(identifier)):[2009A&A...501..941H](https://ui.adsabs.harvard.edu/abs/2009A&A...501..941H), [doi](/source/Doi_(identifier)):[10.1051/0004-6361/200811191](https://doi.org/10.1051%2F0004-6361%2F200811191), [S2CID](/source/S2CID_(identifier)) [118577511](https://api.semanticscholar.org/CorpusID:118577511).

1. ^ [***a***](#cite_ref-Danziger_Faber_1972_7-0) [***b***](#cite_ref-Danziger_Faber_1972_7-1) Danziger, I. J.; Faber, S. M. (May 1972), "Rotation of evolving A and F stars", *Astronomy and Astrophysics*, **18**: 428, [Bibcode](/source/Bibcode_(identifier)):[1972A&A....18..428D](https://ui.adsabs.harvard.edu/abs/1972A&A....18..428D).

1. **[^](#cite_ref-SIMBAD_8-0)** ["psi02 Dra -- Star"](http://simbad.u-strasbg.fr/simbad/sim-id?Ident=psi02+Dra), *SIMBAD Astronomical Database*, Centre de Données astronomiques de Strasbourg, retrieved 2017-05-29.

1. **[^](#cite_ref-Eggleton2008_9-0)** Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", *Monthly Notices of the Royal Astronomical Society*, **389** (2): 869–879, [arXiv](/source/ArXiv_(identifier)):[0806.2878](https://arxiv.org/abs/0806.2878), [Bibcode](/source/Bibcode_(identifier)):[2008MNRAS.389..869E](https://ui.adsabs.harvard.edu/abs/2008MNRAS.389..869E), [doi](/source/Doi_(identifier)):[10.1111/j.1365-2966.2008.13596.x](https://doi.org/10.1111%2Fj.1365-2966.2008.13596.x), [S2CID](/source/S2CID_(identifier)) [14878976](https://api.semanticscholar.org/CorpusID:14878976).

1. **[^](#cite_ref-Sinnott_Perryman_1997_10-0)** Sinnott, Roger W.; Perryman, Michael A. C. (1997), *Millennium Star Atlas*, vol. 3, Sky Publishing Corporation and the European Space Agency, p. 1054, [ISBN](/source/ISBN_(identifier)) [0-933346-84-0](https://en.wikipedia.org/wiki/Special:BookSources/0-933346-84-0).

v t e Constellation of Draco List of stars in Draco Draco in Chinese astronomy Stars Bayer α (Thuban) β (Rastaban) γ (Eltanin) δ (Altais) ε (Tyl) ζ (Aldhibah) η (Athebyne) θ ι (Edasich) κ λ (Giausar) μ (Alrakis) ν (Kuma) ξ (Grumium) ο π ρ σ (Alsafi) τ υ φ χ ψ1 (Dziban) ψ2 ω Flamsteed 4 6 7 (Tianyi) 8 (Taiyi) 10 (i) 15 (A) 18 (g) 19 (h) 26 36 39 (b) 42 (Fafnir) 45 (d) 50 59 64 (e) 68 Variable TW YY AG BY CL CM CX DO EK HP V581 HR 3751 4126 4934 5811 6237 6518 6618 (Alruba) 6817 7137 7783 HD 109246 (Funi) 101364 128717 147379 156279 158259 176693 191939 Other 2MASS 1237+6526 2MASS J17554042+6551277 G 240-72 GD 356 Gliese 420 Gliese 625 Gliese 687 GRW +70 8247 Kepler-4 Kepler-10 Kepler-12 Kepler-90 Kepler-296 KOI-256 LP 71-82 Qatar-1 SDSS J1240+6710 Struve 2398 TOI-1136 WD 1856+534 WISE 1647+5632 WISE 1841+7000 Exoplanets HD 139357 b HD 167042 b ι Dra b (Hypatia) Kepler-4b Kepler-10b c Kepler-12b Kepler-90e f g h i Kepler-296b c d e f TOI-1452 b TrES-2b Star clusters LAMOST 1 Nebulae Cat's Eye Nebula NGC 6742 Galaxies NGC 3147 3197 3735 4121 4125 4221 4236 4319 4331 4332 4363 4441 4513 4545 4589 5678 5777 5866 5866B 5879 5905 5907 5949 5963 5965 5982 5985 6090 6248 6285 6286 6338 6340 6365 6373 6394 6412 6503 6505 6566 6621 6622 6670 6676 6786 6789 Other 1ES 1927+654 1ES 1959+650 3C 249.1 3C 305 3C 319 3C 343 3C 343.1 3C 351 3C 356 3C 371 3C 380 3C 390.3 3C 401 4C +72.26 4C 73.08 8C 1241+735 Abell 2218 BCG Bean galaxy Beaver galaxy BZQ J1727+5510 Draco Dwarf Draco II GB 1508+5714 Goldfish galaxy H1821+643 HFLS3 IERS B1946+708 IRAS F17179+5444 IRAS 18580+6527 J120011.1+680924.8 KKR 25 Markarian 817 Markarian 876 Original TRG PGC 39058 Porphyrion QSO B1823+568 RGZ J172749.5+534647 S5 1803+784 S5 2007+777 SDSS J1715+6008 Tadpole Galaxy UGC 9391 UGC 9405 UGC 11241 UGC 11411 WISEA J145223.62+611707.5 WN B1851+5707 Galaxy clusters Abell 2218 CL1358+62 Draco Supercluster NGC 5866 Group Astronomical events SN 2003jb SN 2005B SN 2016aps Swift J1644+57 Category

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Adapted from the Wikipedia article [Psi2 Draconis](https://en.wikipedia.org/wiki/Psi2_Draconis) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Psi2_Draconis?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.