# Omega Draconis

> Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Omega_Draconis
> Markdown URL: https://mediated.wiki/source/Omega_Draconis.md
> Source: https://en.wikipedia.org/wiki/Omega_Draconis
> Source revision: 1335892844
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)

Star in the constellation Draco

Omega Draconis Location of ω Draconis (circled in red) Observation data Epoch J2000 Equinox J2000 Constellation Draco Right ascension 17h 36m 57.09431s[1] Declination +68° 45′ 28.6815″[1] Apparent magnitude (V) 4.80[2] Characteristics Evolutionary stage main sequence[1] Spectral type F5V[3] U−B color index −0.01[2] B−V color index +0.43[2] Astrometry Radial velocity (Rv) −13.98±0.02[4] km/s Proper motion (μ) RA: +1.690[1] mas/yr Dec.: +321.452[1] mas/yr Parallax (π) 42.0939±0.1425 mas[1] Distance 77.5 ± 0.3 ly (23.76 ± 0.08 pc) Absolute magnitude (MV) 2.95[5] Orbit[6] Period (P) 5.2797766±0.0000044 d Semi-major axis (a) 3.469±0.017 mas Eccentricity (e) 0.00220±0.00031 Inclination (i) 151.4±1.1° Longitude of the node (Ω) 1.23±0.32° Periastron epoch (T) JD 2454349.083±0.083 Argument of periastron (ω) (secondary) 314.8±5.6° Semi-amplitude (K1) (primary) 36.254±0.016 km/s Semi-amplitude (K2) (secondary) 44.720±0.016 km/s Details ω Dra A Mass 1.46±0.16 M☉ Luminosity 5.61[5] L☉ Temperature 6,500 K Metallicity [Fe/H] 0.18±0.05[5] dex Age 1.9[5] Gyr ω Dra B Mass 1.18±0.13 M☉ Temperature 5,900 K Metallicity [Fe/H] 0.0 dex Other designations ω Dra, 28 Dra, BD+68°949, GJ 4017, HD 160922, HIP 86201, HR 6596, SAO 17576 Database references SIMBAD data

**Omega Draconis**, [Latinized](/source/Latinisation_of_names) from **ω Draconis** and also known as **28 Draconis**, is a [binary star](/source/Binary_star) in the [constellation](/source/Constellation) of [Draco](/source/Draco_(constellation)). The system is fairly close, and is located about 78 [light-years](/source/Light-year) (24 [parsecs](/source/Parsec)) away, based on its [parallax](/source/Stellar_parallax).[1]

Omega Draconis is a [spectroscopic binary](/source/Spectroscopic_binary), which means the two stellar components are too close to be [resolved](/source/Angular_resolution) but periodic [Doppler shifts](/source/Doppler_shift) in their [spectra](/source/Spectrum) indicate orbital motion. In this case, light from both stars can be detected, and it is a double-lined spectroscopic binary. The [orbital period](/source/Orbital_period) of the system is 5.28 days, and the [eccentricity](/source/Orbital_eccentricity) of the system is 0.00220, implying a nearly circular [orbit](/source/Orbit). The primary has a mass of 1.46 [M☉](/source/Solar_mass), and is an [F-type main-sequence star](/source/F-type_main-sequence_star). The secondary is less massive, at 1.18 M☉.[6]

## Nomenclature

With [27 Draconis](/source/27_Draconis), it composed the Arabs' الأظفار الذئب *al-ʼaẓfār al-dhiʼb*, "the hyena's claws" in the asterism of the [Mother Camels](/source/Mother_Camels).[7] The two stars have been distinguished as *Adfar Aldib I* (ω) and *Adfar Aldib II* (27 Draconis).[8]

In [Chinese](/source/Chinese_language), 尚書 (*Shàng Shū*), meaning *[Royal Secretary](/source/Purple_Forbidden_enclosure)*, refers to an asterism consisting of ω Draconis, [15 Draconis](/source/15_Draconis), [18 Draconis](/source/18_Draconis) and [19 Draconis](/source/19_Draconis).[9] Consequently, ω Draconis itself is known as 尚書一 (*Shàng Shū yī*, English: the First Star of Royal Secretary.).[10]

## References

1. ^ [***a***](#cite_ref-dr3_1-0) [***b***](#cite_ref-dr3_1-1) [***c***](#cite_ref-dr3_1-2) [***d***](#cite_ref-dr3_1-3) [***e***](#cite_ref-dr3_1-4) [***f***](#cite_ref-dr3_1-5) [***g***](#cite_ref-dr3_1-6) 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%3D1637717179389828224%26-go+%25%23Sesame%23%25%26) at [VizieR](/source/VizieR).

1. ^ [***a***](#cite_ref-UBV_2-0) [***b***](#cite_ref-UBV_2-1) [***c***](#cite_ref-UBV_2-2) Johnson, H. L. (1966). "UBVRIJKL Photometry of the Bright Stars". *Communications of the Lunar and Planetary Laboratory*. **4**: 99. [Bibcode](/source/Bibcode_(identifier)):[1966CoLPL...4...99J](https://ui.adsabs.harvard.edu/abs/1966CoLPL...4...99J).

1. **[^](#cite_ref-3)** Eggen, O. (1957). ["Distribution of the nearer bright stars in the color-luminosity array"](https://doi.org/10.1086%2F107457). *The Astronomical Journal*. **62**: 45. [Bibcode](/source/Bibcode_(identifier)):[1957AJ.....62...45E](https://ui.adsabs.harvard.edu/abs/1957AJ.....62...45E). [doi](/source/Doi_(identifier)):[10.1086/107457](https://doi.org/10.1086%2F107457).

1. **[^](#cite_ref-SB9_4-0)** Pourbaix, D.; et al. (2004). "SB9: The ninth catalogue of spectroscopic binary orbits". *Astronomy and Astrophysics*. **424** (2): 727–732. [arXiv](/source/ArXiv_(identifier)):[astro-ph/0406573](https://arxiv.org/abs/astro-ph/0406573). [Bibcode](/source/Bibcode_(identifier)):[2004A&A...424..727P](https://ui.adsabs.harvard.edu/abs/2004A&A...424..727P). [doi](/source/Doi_(identifier)):[10.1051/0004-6361:20041213](https://doi.org/10.1051%2F0004-6361%3A20041213). [S2CID](/source/S2CID_(identifier)) [119387088](https://api.semanticscholar.org/CorpusID:119387088).

1. ^ [***a***](#cite_ref-Anderson2012_5-0) [***b***](#cite_ref-Anderson2012_5-1) [***c***](#cite_ref-Anderson2012_5-2) [***d***](#cite_ref-Anderson2012_5-3) Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", *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), [S2CID](/source/S2CID_(identifier)) [119257644](https://api.semanticscholar.org/CorpusID:119257644).

1. ^ [***a***](#cite_ref-Konacki_6-0) [***b***](#cite_ref-Konacki_6-1) Konacki, Maciej; et al. (2010). "High-precision Orbital and Physical Parameters of Double-lined Spectroscopic Binary Stars—HD78418, HD123999, HD160922, HD200077, and HD210027". *The Astrophysical Journal*. **719** (2): 1293–1314. [arXiv](/source/ArXiv_(identifier)):[0910.4482](https://arxiv.org/abs/0910.4482). [Bibcode](/source/Bibcode_(identifier)):[2010ApJ...719.1293K](https://ui.adsabs.harvard.edu/abs/2010ApJ...719.1293K). [doi](/source/Doi_(identifier)):[10.1088/0004-637X/719/2/1293](https://doi.org/10.1088%2F0004-637X%2F719%2F2%2F1293). [S2CID](/source/S2CID_(identifier)) [119253596](https://api.semanticscholar.org/CorpusID:119253596).

1. **[^](#cite_ref-allen1899_7-0)** [Allen, Richard Hinckley](/source/Richard_Hinckley_Allen) (1899), *Star-Names and Their Meanings*, New York: G. E. Stechert, p. 212

1. **[^](#cite_ref-rhoads1971_8-0)** Rhoads, Jack W. (November 15, 1971), [*Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars*](https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19720005197_1972005197.pdf) (PDF), Jet Propulsion Laboratory, California Institute of Technology.

1. **[^](#cite_ref-ridpathdraco_9-0)** [Ian Ridpath's Startales - Drco the Dragon](http://www.ianridpath.com/startales/draco.htm)

1. **[^](#cite_ref-10)** (in Chinese) [AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 10 日](http://aeea.nmns.edu.tw/2006/0606/ap060610.html) [Archived](https://web.archive.org/web/20110521234349/http://aeea.nmns.edu.tw/2006/0606/ap060610.html) 2011-05-21 at the [Wayback Machine](/source/Wayback_Machine)

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

---
Adapted from the Wikipedia article [Omega Draconis](https://en.wikipedia.org/wiki/Omega_Draconis) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Omega_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.