# 4 Draconis

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Variable star in the constellation Draco

4 Draconis Location of 4 Draconis (circled in red) Observation data Epoch J2000.0 Equinox J2000.0 Constellation Draco Right ascension 12h 30m 06.66200s[1] Declination +69° 12′ 03.9742″[1] Apparent magnitude (V) 4.90 - 5.12[2] Characteristics Evolutionary stage AGB + ?[3] Spectral type M3+ IIIa[4] Variable type Z Andromedae[2] Astrometry Radial velocity (Rv) −15[5] km/s Proper motion (μ) RA: −57.311[1] mas/yr Dec.: −50.365[1] mas/yr Parallax (π) 5.7233±0.1880 mas[1] Distance 570 ± 20 ly (175 ± 6 pc) Absolute magnitude (MV) −1.37[6] Orbit[7] Primary 4 Draconis A (red giant) Name 4 Draconis B Period (P) 1,703±3 d Semi-major axis (a) 82±4 Gm ( a⋅sin(i) ) Eccentricity (e) 0.30±0.05 Periastron epoch (T) 2442868.5 Argument of periastron (ω) (primary) 244±9° Semi-amplitude (K1) (primary) 3.67±0.19 km/s Details red giant Mass 1.64±0.2[8] M☉ Radius 111.0+9.30 −11.2[8] R☉ Luminosity 2,122±419[8] L☉ Surface gravity (log g) 1.24[8] cgs Temperature 3,718±69[8] K Age 1.97±0.57[8] Gyr white dwarf Mass ~0.8[9] M☉ Radius 0.0094[9] R☉ Luminosity (6.6–22)×10−3[9] L☉ Surface gravity (log g) 8.4[9] cgs Temperature 20,000±3,000[9] K Other designations CQ Dra, HD 108907, HR 4765, HIP 60998, SAO 15816[10] Database references SIMBAD data

**4 Draconis**, also known as **HR 4765** and **CQ Draconis**, is a star about 570 [light years](/source/Light_year) from the Earth, in the constellation [Draco](/source/Draco_(constellation)).[1] It is a 5th [magnitude](/source/Apparent_magnitude) star, so it will be faintly visible to the [naked eye](/source/Naked_eye) of an observer far from [city lights](/source/Light_pollution).[1] It is a variable star, whose brightness varies slightly from 4.90 to 5.12 over a period of 4.66 years.[2]

[Light curves](/source/Light_curve) for CQ Draconis, adapted from Skopal *et al.* (1992)[11] The brightening seen (most clearly in the ultraviolet) after June 1990 occurred shortly after the [periastron](/source/Apsis) passage.[12]

In 1967, Olin Eggen discovered that 4 Draconis is a variable star, during a multicolor [photometric](/source/Photometry_(astronomy)) survey of red stars.[13] In 1973 it was given the [variable star designation](/source/Variable_star_designation) CQ Draconis.[14]

Until the year 1985, 4 Draconis was thought to be a normal [red giant](/source/Red_giant) star. In 1985, Dieter Reimers announced that the [International Ultraviolet Explorer](/source/International_Ultraviolet_Explorer) had detected a hot companion to the red giant, which itself appeared to be a binary [cataclysmic variable star](/source/Cataclysmic_variable_star), making the complete system a triple star.[15] However a 2003 study by Peter Wheatley *et al.*, who examined [ROSAT](/source/ROSAT) [X-ray](/source/X-ray) data for the star, concluded that the hot companion was more apt to be a single [white dwarf](/source/White_dwarf), rather than a binary, and that the white dwarf is accreting material from the red giant.[16] There does not yet appear to be a consensus about the multiplicity; some later studies consider 4 Draconis to be a binary,[17][18] and some a triple.[19][9]

In 1987, Alexander Brown announced that 6 cm wavelength [radio](/source/Radio) emission had been detected by the [Very Large Array](/source/Very_Large_Array). The strength of the radio emission was variable on a timescale of weeks to months.[20]

It is possible that an outburst of 4 Draconis was the "[guest star](/source/Guest_star_(astronomy))" reported by Chinese astronomers in the year 369 CE, in the constellation Zigong.[21]

## 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%3D1683014206596170240%26-go+%25%23Sesame%23%25%26) at [VizieR](/source/VizieR).

1. ^ [***a***](#cite_ref-IVSI_2-0) [***b***](#cite_ref-IVSI_2-1) [***c***](#cite_ref-IVSI_2-2) ["CQ Dra"](https://www.aavso.org/vsx/index.php?view=detail.top&oid=13789). *The International Variable Star Index*. AAVSO. Retrieved 26 February 2023.

1. **[^](#cite_ref-ortiz2016_3-0)** Ortiz, Roberto; Guerrero, Martín A. (2016). ["Ultraviolet emission from main-sequence companions of AGB stars"](https://doi.org/10.1093%2Fmnras%2Fstw1547). *Monthly Notices of the Royal Astronomical Society*. **461** (3): 3036. [arXiv](/source/ArXiv_(identifier)):[1606.09086](https://arxiv.org/abs/1606.09086). [Bibcode](/source/Bibcode_(identifier)):[2016MNRAS.461.3036O](https://ui.adsabs.harvard.edu/abs/2016MNRAS.461.3036O). [doi](/source/Doi_(identifier)):[10.1093/mnras/stw1547](https://doi.org/10.1093%2Fmnras%2Fstw1547).

1. **[^](#cite_ref-perkins_4-0)** Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins catalog of revised MK types for the cooler stars". *The Astrophysical Journal Supplement Series*. **71**: 245. [Bibcode](/source/Bibcode_(identifier)):[1989ApJS...71..245K](https://ui.adsabs.harvard.edu/abs/1989ApJS...71..245K). [doi](/source/Doi_(identifier)):[10.1086/191373](https://doi.org/10.1086%2F191373).

1. **[^](#cite_ref-Famaey2009_5-0)** Famaey, B.; Pourbaix, D.; Frankowski, A.; van Eck, S.; Mayor, M.; Udry, S.; Jorissen, A. (May 2009). ["Spectroscopic binaries among Hipparcos M giants,. I. Data, orbits, and intrinsic variations"](https://doi.org/10.1051%2F0004-6361%2F200810698). *Astronomy and Astrophysics*. **498** (2): 627–640. [arXiv](/source/ArXiv_(identifier)):[0901.0934](https://arxiv.org/abs/0901.0934). [Bibcode](/source/Bibcode_(identifier)):[2009A&A...498..627F](https://ui.adsabs.harvard.edu/abs/2009A&A...498..627F). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/200810698](https://doi.org/10.1051%2F0004-6361%2F200810698).

1. **[^](#cite_ref-xhip_6-0)** 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. **[^](#cite_ref-Reimers1988_7-0)** Reimers, D.; Griffin, R. F.; Brown, A. (March 1988). "4 Draconis : a unique triple system containing an M3 giant and a cataclysmic binary". *Astronomy and Astrophysics*. **193**: 180–184. [Bibcode](/source/Bibcode_(identifier)):[1988A&A...193..180R](https://ui.adsabs.harvard.edu/abs/1988A&A...193..180R).

1. ^ [***a***](#cite_ref-baines_8-0) [***b***](#cite_ref-baines_8-1) [***c***](#cite_ref-baines_8-2) [***d***](#cite_ref-baines_8-3) [***e***](#cite_ref-baines_8-4) [***f***](#cite_ref-baines_8-5) Baines, Ellyn K.; Armstrong, J. Thomas; Schmitt, Henrique R.; Zavala, R. T.; Benson, James A.; Hutter, Donald J.; Tycner, Christopher; van Belle, Gerard T. (2017). ["Fundamental parameters of 87 stars from the Navy Precision Optical Interferometer"](https://doi.org/10.3847%2F1538-3881%2Faa9d8b). *The Astronomical Journal*. **155** (1): 16. [arXiv](/source/ArXiv_(identifier)):[1712.08109](https://arxiv.org/abs/1712.08109). [Bibcode](/source/Bibcode_(identifier)):[2018AJ....155...30B](https://ui.adsabs.harvard.edu/abs/2018AJ....155...30B). [doi](/source/Doi_(identifier)):[10.3847/1538-3881/aa9d8b](https://doi.org/10.3847%2F1538-3881%2Faa9d8b). [S2CID](/source/S2CID_(identifier)) [119427037](https://api.semanticscholar.org/CorpusID:119427037).

1. ^ [***a***](#cite_ref-Sion2017_9-0) [***b***](#cite_ref-Sion2017_9-1) [***c***](#cite_ref-Sion2017_9-2) [***d***](#cite_ref-Sion2017_9-3) [***e***](#cite_ref-Sion2017_9-4) [***f***](#cite_ref-Sion2017_9-5) Sion, Edward M.; Godon, Patrick; Mikolajewska, Joanna; Sabra, Bassem; Kolobow, Craig (April 2017). ["FUSE Spectroscopy of the Accreting Hot Components in Symbiotic Variables"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5810147). *The Astronomical Journal*. **153** (4): 160. [arXiv](/source/ArXiv_(identifier)):[1702.07341](https://arxiv.org/abs/1702.07341). [Bibcode](/source/Bibcode_(identifier)):[2017AJ....153..160S](https://ui.adsabs.harvard.edu/abs/2017AJ....153..160S). [doi](/source/Doi_(identifier)):[10.3847/1538-3881/aa62a9](https://doi.org/10.3847%2F1538-3881%2Faa62a9). [PMC](/source/PMC_(identifier)) [5810147](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5810147). [PMID](/source/PMID_(identifier)) [29456255](https://pubmed.ncbi.nlm.nih.gov/29456255).

1. **[^](#cite_ref-SIMBAD_10-0)** ["4 Dra -- Spectroscopic Binary"](http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=4+Dra+--+Spectroscopic+Binary). *[SIMBAD](/source/SIMBAD)*. [Centre de données astronomiques de Strasbourg](/source/Centre_de_donn%C3%A9es_astronomiques_de_Strasbourg). Retrieved 2023-02-26.

1. **[^](#cite_ref-Skopal1992_11-0)** Skopal, A.; Hric, L.; Urban, Z.; Pigulski, A.; Blanco, C.; Papousek, J.; Hanzl, D.; Agerer, F.; Niarchos, P.; Rovithis-Livaniou, H.; Rovithis, P.; Tsvetkova, K.; Semkov, E.; Velic, Z.; Michalek, F.; Komacka, L.; Schweitzer, E.; Korth, S. (July 1992). "Photometry of symbiotic stars - an international campaign. III. Z And, EG And, R Aqr, UV Aur, TX CVn, T CrB, BF Cyg, CH Cyg, CI Cyg, V 1016 Cyg, V 1329 Cyg, AG Dra, CQ DRA (4 Dra), YY Her, V 443 Her, SS Lep, RS Oph, AG Peg, AX Per, HM Sge, FG Ser (AS 296), PU Vul". *Contributions of the Astronomical Observatory Skalnate Pleso*. **22**: 131–172. [Bibcode](/source/Bibcode_(identifier)):[1992CoSka..22..131S](https://ui.adsabs.harvard.edu/abs/1992CoSka..22..131S).

1. **[^](#cite_ref-Hric1991_12-0)** Hric, L.; Urban, Z. (November 1991). ["The Symbiotic-Like/Cataclysmic Triple System 4 Dra (= CQ Dra): Detection of a Post-Periastron Passage Brightening"](https://ibvs.konkoly.hu/pub/ibvs/3601/3683.pdf) (PDF). *Information Bulletin on Variable Stars*. **3683**: 1. [Bibcode](/source/Bibcode_(identifier)):[1991IBVS.3683....1H](https://ui.adsabs.harvard.edu/abs/1991IBVS.3683....1H). Retrieved 28 February 2023.

1. **[^](#cite_ref-Eggen1967_13-0)** Eggen, O. J. (September 1967). ["Narrow and broad band photometry of red stars : I. Northern giants"](https://doi.org/10.1086%2F190158). *Astrophysical Journal Supplement Series*. **14**: 307–358. [Bibcode](/source/Bibcode_(identifier)):[1967ApJS...14..307E](https://ui.adsabs.harvard.edu/abs/1967ApJS...14..307E). [doi](/source/Doi_(identifier)):[10.1086/190158](https://doi.org/10.1086%2F190158).

1. **[^](#cite_ref-Kukarkin1973_14-0)** Kukarkin, B. V.; Kholopov, P. N.; Kukarkina, N. P.; Perova, N. B. (October 1973). ["59th Name-List of Variable Stars"](https://ibvs.konkoly.hu/pub/ibvs/0801/0834.pdf) (PDF). *Information Bulletin on Variable Stars*. **834**: 1. [Bibcode](/source/Bibcode_(identifier)):[1973IBVS..834....1K](https://ui.adsabs.harvard.edu/abs/1973IBVS..834....1K). Retrieved 27 February 2023.

1. **[^](#cite_ref-Reimers1985_15-0)** Reimers, D. (January 1985). "Discovery of a cataclysmic variable type companion of the M3 III giant 4 DRA with IUE". *Astronomy and Astrophysics*. **142**: L16–L18. [Bibcode](/source/Bibcode_(identifier)):[1985A&A...142L..16R](https://ui.adsabs.harvard.edu/abs/1985A&A...142L..16R).

1. **[^](#cite_ref-Wheatley2003_16-0)** Wheatley, Peter J.; Mukai, Koji; de Martino, Domitilla (December 2003). ["X-ray observations of 4 Draconis: symbiotic binary or cataclysmic triple?"](https://doi.org/10.1111%2Fj.1365-2966.2003.07149.x). *Monthly Notices of the Royal Astronomical Society*. **346** (3): 855–860. [arXiv](/source/ArXiv_(identifier)):[astro-ph/0309410](https://arxiv.org/abs/astro-ph/0309410). [Bibcode](/source/Bibcode_(identifier)):[2003MNRAS.346..855W](https://ui.adsabs.harvard.edu/abs/2003MNRAS.346..855W). [doi](/source/Doi_(identifier)):[10.1111/j.1365-2966.2003.07149.x](https://doi.org/10.1111%2Fj.1365-2966.2003.07149.x).

1. **[^](#cite_ref-Skopal2005_17-0)** Skopal, A. (August 2005). ["Accretion-powered symbiotic binaries: EG And and CQ Dra"](http://aspbooks.org/publications/330/463.pdf) (PDF). *The Astrophysics of Cataclysmic Variables and Related Objects, Proceedings of ASP Conference*. **330**: 463–464. [Bibcode](/source/Bibcode_(identifier)):[2005ASPC..330..463S](https://ui.adsabs.harvard.edu/abs/2005ASPC..330..463S). Retrieved 28 February 2023.

1. **[^](#cite_ref-Nuñez2016_18-0)** Nuñez, N. E.; Nelson, T.; Mukai, K.; Sokoloski, J. L.; Luna, G. J. M. (June 2016). ["Symbiotic Stars in X-Rays. III. Suzaku Observations"](https://doi.org/10.3847%2F0004-637X%2F824%2F1%2F23). *The Astrophysical Journal*. **824** (1): 23. [arXiv](/source/ArXiv_(identifier)):[1604.05980](https://arxiv.org/abs/1604.05980). [Bibcode](/source/Bibcode_(identifier)):[2016ApJ...824...23N](https://ui.adsabs.harvard.edu/abs/2016ApJ...824...23N). [doi](/source/Doi_(identifier)):[10.3847/0004-637X/824/1/23](https://doi.org/10.3847%2F0004-637X%2F824%2F1%2F23).

1. **[^](#cite_ref-DiStefano2020_19-0)** Di Stefano, R. (April 2020). ["Mass from a third star: transformations of close compact-object binaries within hierarchical triples"](https://doi.org/10.1093%2Fmnras%2Fstaa220). *Monthly Notices of the Royal Astronomical Society*. **493** (2): 1855–1873. [arXiv](/source/ArXiv_(identifier)):[1805.09338](https://arxiv.org/abs/1805.09338). [Bibcode](/source/Bibcode_(identifier)):[2020MNRAS.493.1855D](https://ui.adsabs.harvard.edu/abs/2020MNRAS.493.1855D). [doi](/source/Doi_(identifier)):[10.1093/mnras/staa220](https://doi.org/10.1093%2Fmnras%2Fstaa220).

1. **[^](#cite_ref-Brown1987_20-0)** Brown, Alexander (January 1987). "Variable Radio Emission from the 4 Draconis System". *Astrophysical Journal Letters*. **312**: L51–L53. [Bibcode](/source/Bibcode_(identifier)):[1987ApJ...312L..51B](https://ui.adsabs.harvard.edu/abs/1987ApJ...312L..51B). [doi](/source/Doi_(identifier)):[10.1086/184818](https://doi.org/10.1086%2F184818).

1. **[^](#cite_ref-Hoffmann2020_21-0)** Hoffmann, Susanne M.; Vogt, Nikolaus (September 2020). ["A search for the modern counterparts of the Far Eastern guest stars 369 CE, 386 CE and 393 CE"](https://doi.org/10.1093%2Fmnras%2Fstaa1970). *Monthly Notices of the Royal Astronomical Society*. **497** (2): 1419–1433. [arXiv](/source/ArXiv_(identifier)):[2007.01013](https://arxiv.org/abs/2007.01013). [Bibcode](/source/Bibcode_(identifier)):[2020MNRAS.497.1419H](https://ui.adsabs.harvard.edu/abs/2020MNRAS.497.1419H). [doi](/source/Doi_(identifier)):[10.1093/mnras/staa1970](https://doi.org/10.1093%2Fmnras%2Fstaa1970).

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 [4 Draconis](https://en.wikipedia.org/wiki/4_Draconis) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/4_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.