# 59 Draconis

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Star in the constellation Draco

59 Draconis Location of 59 Draconis (circled in red) Observation data Epoch J2000 Equinox J2000 Constellation Draco[1] Right ascension 19h 09m 09.88146s[2] Declination +76° 33′ 37.8138″[2] Apparent magnitude (V) 5.11[1] Characteristics Evolutionary stage main sequence[2] Spectral type A9V[3] B−V color index 0.308[1] Variable type γ Dor?[3] Astrometry Radial velocity (Rv) −3.77±0.50[2] km/s Proper motion (μ) RA: +52.390 mas/yr[2] Dec.: −119.469 mas/yr[2] Parallax (π) 36.5363±0.1299 mas[2] Distance 89.3 ± 0.3 ly (27.37 ± 0.10 pc) Absolute magnitude (MV) 2.93[1] Orbit[3] Period (P) 28.44±0.01 d Semi-major axis (a) 0.22 AU Eccentricity (e) 0.20±0.01 Periastron epoch (T) 2453244.3±0.3 JD Argument of periastron (ω) (secondary) 56±4° Semi-amplitude (K1) (primary) 1.20±0.02 km/s Details A Mass 1.447+0.014 −0.015[4] M☉ Radius 1.488+0.031 −0.033[4] R☉ Luminosity 4.861+0.285 −0.290[4] L☉ Surface gravity (log g) 4.18±0.21[5] cgs Temperature 7053±194[5] K Rotational velocity (v sin i) 53.0±1.1[5] km/s Age 436+156 −203[4] Myr B Mass ≥25[3] MJup Other designations 59 Dra, NSV 11824, BD+76 717, GC 26484, GJ 9649, GJ 748.1, HD 180777, HIP 94083, HR 7312, SAO 9341, PPM 10093, PLX 4497[6] Database references SIMBAD data

**59 Draconis** is a star with a likely [brown dwarf](/source/Brown_dwarf) companion, located 89.3 [light-years](/source/Light-year) (27.4 [parsecs](/source/Parsec)) away in the constellation [Draco](/source/Draco_(constellation)). With an [apparent magnitude](/source/Apparent_magnitude) of 5.1, it is faintly visible to the [naked eye](/source/Naked_eye) under good viewing conditions. In [Chinese astronomy](/source/Chinese_astronomy), this star is known as Tiānzhùsì (天柱四), meaning it is the fourth star of the asterism Tiānzhù (天柱, Celestial Pillar).[8]

The [stellar classification](/source/Stellar_classification) of 59 Draconis is A9V,[3] indicating that it is an [A-type main-sequence star](/source/A-type_main-sequence_star) that is generating energy through [hydrogen fusion](/source/Hydrogen_fusion) at its [core](/source/Stellar_core). Other sources classify it as A7V[9] or F0Vs.[1] It has a similar [chemical abundance](/source/Chemical_abundance) to the Sun.[5] The star is listed as a suspected [variable](/source/Variable_star),[10] with [pulsations](/source/Stellar_pulsation) resembling those of [Gamma Doradus stars](/source/Gamma_Doradus_star).[3] It is a candidate member of the [Ursa Major Moving Group](/source/Ursa_Major_Moving_Group) stream,[11][4] though a 2020 study listed its membership probability as only 33%.[12] It appears to be [rotating](/source/Stellar_rotation) with an [inclination](/source/Inclination) of about 28° to the [plane of the sky](/source/Plane_of_the_sky).[4]

The detection of a companion via [Doppler spectroscopy](/source/Doppler_spectroscopy) was announced in 2006.[3] This object orbits with a [period](/source/Orbital_period) of 28.4 days and has a [minimum mass](/source/Minimum_mass) of 25 [MJ](/source/Jupiter_mass), in the range of [brown dwarfs](/source/Brown_dwarf). Since the inclination of the orbit is unknown, the true mass cannot be determined, and it remains possible that it is a star rather than a brown dwarf.[3] [Hipparcos](/source/Hipparcos) [astrometry](/source/Astrometry) has set an upper limit on its mass of 0.27 [M☉](/source/Solar_mass).[13] If confirmed as a brown dwarf, it is within the [brown dwarf desert](/source/Brown_dwarf_desert), a range of orbits where few brown dwarfs are found.[3]

## References

1. ^ [***a***](#cite_ref-xhip_1-0) [***b***](#cite_ref-xhip_1-1) [***c***](#cite_ref-xhip_1-2) [***d***](#cite_ref-xhip_1-3) [***e***](#cite_ref-xhip_1-4) Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". *[Astronomy Letters](/source/Astronomy_Letters)*. **38** (5): 331. [arXiv](/source/ArXiv_(identifier)):[1108.4971](https://arxiv.org/abs/1108.4971). [Bibcode](/source/Bibcode_(identifier)):[2012AstL...38..331A](https://ui.adsabs.harvard.edu/abs/2012AstL...38..331A). [doi](/source/Doi_(identifier)):[10.1134/S1063773712050015](https://doi.org/10.1134%2FS1063773712050015). [XHIP record for this object](https://vizier.cds.unistra.fr/viz-bin/VizieR-4?-ref=VIZ681510a8389ecb&-out.src=V%2F137D%2FXHIP&-nav=cat%3AV%2F137D%26tab%3A{V%2F137D%2FXHIP}%26key%3Asource%3DV%2F137D%2FXHIP%26HTTPPRM%3A&-source=V%2F137D%2FXHIP&-out=HIP&HIP=94083&-out=Comp&-out=Gr&-out=RAJ2000&-out=DEJ2000&-out=Dist&-out=X&-out=Y&-out=Z&-out=SpType&-out=Simbad&-out=Hpmag&-out=Lum&-out=Cst) at [VizieR](/source/VizieR).

1. ^ [***a***](#cite_ref-GaiaDR3_2-0) [***b***](#cite_ref-GaiaDR3_2-1) [***c***](#cite_ref-GaiaDR3_2-2) [***d***](#cite_ref-GaiaDR3_2-3) [***e***](#cite_ref-GaiaDR3_2-4) [***f***](#cite_ref-GaiaDR3_2-5) Vallenari, A.; et al. (Gaia collaboration) (2023). ["*Gaia* Data Release 3. Summary of the content and survey properties"](https://doi.org/10.1051%2F0004-6361%2F202243940). *Astronomy and Astrophysics*. **674**: A1. [arXiv](/source/ArXiv_(identifier)):[2208.00211](https://arxiv.org/abs/2208.00211). [Bibcode](/source/Bibcode_(identifier)):[2023A&A...674A...1G](https://ui.adsabs.harvard.edu/abs/2023A&A...674A...1G). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/202243940](https://doi.org/10.1051%2F0004-6361%2F202243940). [S2CID](/source/S2CID_(identifier)) [244398875](https://api.semanticscholar.org/CorpusID:244398875). [Gaia DR3 record for this source](https://vizier.cds.unistra.fr/viz-bin/VizieR-4?-source=+I%2F355&-from=nav&-nav=cat%3AI%2F355%26tab%3A%7BI%2F355%2Fgaiadr3%7D%26key%3Asource%3D1355%2Fgaiadr3%26HTTPPRM%3A%26-out.add%3D.%26Source%3D%3D%3D2292498687560557056%26-go+%25%23Sesame%23%25%26) at [VizieR](/source/VizieR).

1. ^ [***a***](#cite_ref-Galland2006_3-0) [***b***](#cite_ref-Galland2006_3-1) [***c***](#cite_ref-Galland2006_3-2) [***d***](#cite_ref-Galland2006_3-3) [***e***](#cite_ref-Galland2006_3-4) [***f***](#cite_ref-Galland2006_3-5) [***g***](#cite_ref-Galland2006_3-6) [***h***](#cite_ref-Galland2006_3-7) [***i***](#cite_ref-Galland2006_3-8) Galland, F.; Lagrange, A.-M.; et al. (June 2006). ["Extrasolar planets and brown dwarfs around A-F type stars. IV. A candidate brown dwarf around the A9V pulsating star HD 180777"](https://doi.org/10.1051%2F0004-6361%3A20054079). *[Astronomy and Astrophysics](/source/Astronomy_and_Astrophysics)*. **452** (2): 709–714. [arXiv](/source/ArXiv_(identifier)):[astro-ph/0602592](https://arxiv.org/abs/astro-ph/0602592). [Bibcode](/source/Bibcode_(identifier)):[2006A&A...452..709G](https://ui.adsabs.harvard.edu/abs/2006A&A...452..709G). [doi](/source/Doi_(identifier)):[10.1051/0004-6361:20054079](https://doi.org/10.1051%2F0004-6361%3A20054079).

1. ^ [***a***](#cite_ref-Jones2015_4-0) [***b***](#cite_ref-Jones2015_4-1) [***c***](#cite_ref-Jones2015_4-2) [***d***](#cite_ref-Jones2015_4-3) [***e***](#cite_ref-Jones2015_4-4) [***f***](#cite_ref-Jones2015_4-5) Jones, Jeremy; White, R. J.; et al. (November 2015). ["The Ages of A-Stars. I. Interferometric Observations and Age Estimates for Stars in the Ursa Major Moving Group"](https://doi.org/10.1088%2F0004-637X%2F813%2F1%2F58). *[The Astrophysical Journal](/source/The_Astrophysical_Journal)*. **813** (1): 58. [arXiv](/source/ArXiv_(identifier)):[1508.05643](https://arxiv.org/abs/1508.05643). [Bibcode](/source/Bibcode_(identifier)):[2015ApJ...813...58J](https://ui.adsabs.harvard.edu/abs/2015ApJ...813...58J). [doi](/source/Doi_(identifier)):[10.1088/0004-637X/813/1/58](https://doi.org/10.1088%2F0004-637X%2F813%2F1%2F58).

1. ^ [***a***](#cite_ref-Saffe2021_5-0) [***b***](#cite_ref-Saffe2021_5-1) [***c***](#cite_ref-Saffe2021_5-2) [***d***](#cite_ref-Saffe2021_5-3) Saffe, C.; Miquelarena, P.; et al. (March 2021). ["Chemical analysis of early-type stars with planets"](https://doi.org/10.1051%2F0004-6361%2F202040132). *[Astronomy & Astrophysics](/source/Astronomy_%26_Astrophysics)*. **647**: A49. [arXiv](/source/ArXiv_(identifier)):[2101.04416](https://arxiv.org/abs/2101.04416). [Bibcode](/source/Bibcode_(identifier)):[2021A&A...647A..49S](https://ui.adsabs.harvard.edu/abs/2021A&A...647A..49S). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/202040132](https://doi.org/10.1051%2F0004-6361%2F202040132).

1. **[^](#cite_ref-SIMBAD_6-0)** ["* 59 Dra"](http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+59+Dra). *[SIMBAD](/source/SIMBAD)*. [Centre de données astronomiques de Strasbourg](/source/Centre_de_donn%C3%A9es_astronomiques_de_Strasbourg). Retrieved 18 June 2025.

1. **[^](#cite_ref-Yi1981_7-0)** Yi, Shitong (April 1981). 中西对照恒星图表 [*Atlas Comparing Chinese and Western Star Maps and Catalogues*] (in Chinese). 科学出版社.

1. **[^](#cite_ref-8)** [Stellarium](/source/Stellarium_(software)), citing Yi Shitong, 1981[7]

1. **[^](#cite_ref-vanBelle2009_9-0)** van Belle, Gerard T.; von Braun, Kaspar (April 2009). ["Directly Determined Linear Radii and Effective Temperatures of Exoplanet Host Stars"](https://doi.org/10.1088%2F0004-637X%2F694%2F2%2F1085). *[The Astrophysical Journal](/source/The_Astrophysical_Journal)*. **694** (2): 1085–1098. [arXiv](/source/ArXiv_(identifier)):[0901.1206](https://arxiv.org/abs/0901.1206). [Bibcode](/source/Bibcode_(identifier)):[2009ApJ...694.1085V](https://ui.adsabs.harvard.edu/abs/2009ApJ...694.1085V). [doi](/source/Doi_(identifier)):[10.1088/0004-637X/694/2/1085](https://doi.org/10.1088%2F0004-637X%2F694%2F2%2F1085).

1. **[^](#cite_ref-vsx_10-0)** ["NSV 11824"](https://vsx.aavso.org/index.php?view=detail.top&oid=50448). *International Variable Star Index*. [AAVSO](/source/AAVSO). Retrieved 29 June 2025.

1. **[^](#cite_ref-King2003_11-0)** King, Jeremy R.; Villarreal, Adam R.; et al. (April 2003). ["Stellar Kinematic Groups. II. A Reexamination of the Membership, Activity, and Age of the Ursa Major Group"](https://doi.org/10.1086%2F368241). *[The Astronomical Journal](/source/The_Astronomical_Journal)*. **125** (4): 1980–2017. [Bibcode](/source/Bibcode_(identifier)):[2003AJ....125.1980K](https://ui.adsabs.harvard.edu/abs/2003AJ....125.1980K). [doi](/source/Doi_(identifier)):[10.1086/368241](https://doi.org/10.1086%2F368241).

1. **[^](#cite_ref-Ujjwal2020_12-0)** Ujjwal, K.; Kartha, Sreeja S.; et al. (April 2020). ["Analysis of Membership Probability in Nearby Young Moving Groups with Gaia DR2"](https://doi.org/10.3847%2F1538-3881%2Fab76d6). *[The Astronomical Journal](/source/The_Astronomical_Journal)*. **159** (4): 166. [arXiv](/source/ArXiv_(identifier)):[2002.04801](https://arxiv.org/abs/2002.04801). [Bibcode](/source/Bibcode_(identifier)):[2020AJ....159..166U](https://ui.adsabs.harvard.edu/abs/2020AJ....159..166U). [doi](/source/Doi_(identifier)):[10.3847/1538-3881/ab76d6](https://doi.org/10.3847%2F1538-3881%2Fab76d6).

1. **[^](#cite_ref-Sahlmann2011_13-0)** Sahlmann, J.; Ségransan, D.; et al. (January 2011). ["Search for brown-dwarf companions of stars"](https://doi.org/10.1051%2F0004-6361%2F201015427). *[Astronomy and Astrophysics](/source/Astronomy_and_Astrophysics)*. **525**: A95. [arXiv](/source/ArXiv_(identifier)):[1009.5991](https://arxiv.org/abs/1009.5991). [Bibcode](/source/Bibcode_(identifier)):[2011A&A...525A..95S](https://ui.adsabs.harvard.edu/abs/2011A&A...525A..95S). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/201015427](https://doi.org/10.1051%2F0004-6361%2F201015427).

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 [59 Draconis](https://en.wikipedia.org/wiki/59_Draconis) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/59_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.