# 19 Draconis

> Mediated Wiki article. Canonical URL: https://mediated.wiki/source/19_Draconis
> Markdown URL: https://mediated.wiki/source/19_Draconis.md
> Source: https://en.wikipedia.org/wiki/19_Draconis
> Source revision: 1335887348
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)

Star in the constellation Draco

19 Draconis Location of 19 Dra (circled in red) Observation data Epoch J2000 Equinox J2000 Constellation Draco Right ascension 16h 56m 01.68925s[1] Declination +65° 08′ 05.2631″[1] Apparent magnitude (V) 4.89[2] Characteristics Evolutionary stage main sequence[3] Spectral type F8V[4] U−B color index -0.03[2] B−V color index +0.485[2] Astrometry Radial velocity (Rv) −21.00 ± 0.8[5] km/s Proper motion (μ) RA: 237.79[1] mas/yr Dec.: 50.84[1] mas/yr Parallax (π) 65.54±0.33 mas[1] Distance 49.8 ± 0.3 ly (15.26 ± 0.08 pc) Absolute magnitude (MV) 3.98[6] Orbit[6] Period (P) 52.1089 ± 0.0001 d Semi-major axis (a) 20.0 mas Eccentricity (e) 0.2221 ± 0.0002 Inclination (i) 90.5 ± 2.2° Longitude of the node (Ω) 23.5 ± 2.0° Periastron epoch (T) JD 2453427.880 ± 0.007 Argument of periastron (ω) (secondary) 338.46 ± 0.05° Semi-amplitude (K1) (primary) 17.465 ± 0.004 km/s Details[6] 19 Dra A Mass 1.04 M☉ Radius 1.2 R☉ Luminosity 2.02 L☉ Temperature 6298 ± 80 K Metallicity Z = 0.013 ± 0.004 Age 4.7 Gyr 19 Dra B Mass 0.37 M☉ Radius 0.3 R☉ Luminosity 0.02 L☉ Temperature ~3963[note 1] K Other designations BD+65°1157, GJ 648, HD 153597, HIP 82860, HR 6315, SAO 17281 Database references SIMBAD data ARICNS data

19 Draconis in optical light

**19 Draconis**, also known as **h Draconis**, is a [star](/source/Star) system in the [constellation](/source/Constellation) [Draco](/source/Draco_(constellation)). It is visible to the naked eye as a faint, yellow-white hued star with an [apparent visual magnitude](/source/Apparent_visual_magnitude) of 4.89.[2] Based on its [parallax](/source/Stellar_parallax), the system is located about 49.8 [light-years](/source/Light-year) (15.26 [parsecs](/source/Parsec)) away.[1] It is moving closer to the Earth with a heliocentric [radial velocity](/source/Radial_velocity) of −21 km/s.[5]

This is a [binary star](/source/Binary_star) system with an [orbital period](/source/Orbital_period) of 52.1 days and an [eccentricity](/source/Orbital_eccentricity) of 0.22. Only the primary star can be directly detected, via [Doppler shifts](/source/Doppler_shift) or [perturbations](/source/Perturbation_(astronomy)) around the system's barycenter. Using spectroscopy and astrometry, the nature of the secondary star can be inferred. The primary star is an [F-type main-sequence star](/source/F-type_main-sequence_star) with a [stellar classification](/source/Stellar_classification) of F8V,[4] 4% more massive than the [Sun](/source/Sun). Its surface temperature is about 6,298 [K](/source/Kelvin), and it emits just over twice the amount of energy that the Sun does. The secondary is only 37% as massive as the [Sun](/source/Sun), and its luminosity is only 2% that of the Sun. The system is about 4.7 billion years old.[6]

## Notes

1. **[^](#cite_ref-7)** From *L* = 4π*R*2σ*T*eff4, rearranging to make *T*eff = (*L* / 4π*R*2σ)1/4. Where *L* is the luminosity, *R* is the radius, *T*eff is the effective surface temperature and *σ* is the [Stefan–Boltzmann constant](/source/Stefan%E2%80%93Boltzmann_constant).

## References

1. ^ [***a***](#cite_ref-HIP_1-0) [***b***](#cite_ref-HIP_1-1) [***c***](#cite_ref-HIP_1-2) [***d***](#cite_ref-HIP_1-3) [***e***](#cite_ref-HIP_1-4) [***f***](#cite_ref-HIP_1-5) van Leeuwen, F.; et al. (2007). ["Validation of the new Hipparcos reduction"](http://www.aanda.org/index.php?option=com_article&access=bibcode&Itemid=129&bibcode=2007A%2526A...474..653VFUL). *Astronomy and Astrophysics*. **474** (2): 653–664. [arXiv](/source/ArXiv_(identifier)):[0708.1752](https://arxiv.org/abs/0708.1752). [Bibcode](/source/Bibcode_(identifier)):[2007A&A...474..653V](https://ui.adsabs.harvard.edu/abs/2007A&A...474..653V). [doi](/source/Doi_(identifier)):[10.1051/0004-6361:20078357](https://doi.org/10.1051%2F0004-6361%3A20078357). [S2CID](/source/S2CID_(identifier)) [18759600](https://api.semanticscholar.org/CorpusID:18759600).

1. ^ [***a***](#cite_ref-EgUBV_2-0) [***b***](#cite_ref-EgUBV_2-1) [***c***](#cite_ref-EgUBV_2-2) [***d***](#cite_ref-EgUBV_2-3) Mermilliod, J.-C. (1986). ["Compilation of Eggen's UBV data, transformed to UBV (unpublished)"](http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?1986EgUBV........0M&db_key=AST&nosetcookie=1). *Catalogue of Eggen's UBV Data*. [Bibcode](/source/Bibcode_(identifier)):[1986EgUBV........0M](https://ui.adsabs.harvard.edu/abs/1986EgUBV........0M).

1. **[^](#cite_ref-dr3_3-0)** 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%3D1635375460142367104%26-go+%25%23Sesame%23%25%26) at [VizieR](/source/VizieR).

1. ^ [***a***](#cite_ref-Abt_4-0) [***b***](#cite_ref-Abt_4-1) Abt, Helmut A. (2009). "MK Classifications of Spectroscopic Binaries". *The Astrophysical Journal Supplement*. **180** (1): 117–18. [Bibcode](/source/Bibcode_(identifier)):[2009ApJS..180..117A](https://ui.adsabs.harvard.edu/abs/2009ApJS..180..117A). [doi](/source/Doi_(identifier)):[10.1088/0067-0049/180/1/117](https://doi.org/10.1088%2F0067-0049%2F180%2F1%2F117). [S2CID](/source/S2CID_(identifier)) [122811461](https://api.semanticscholar.org/CorpusID:122811461).

1. ^ [***a***](#cite_ref-Gontcharov2006_5-0) [***b***](#cite_ref-Gontcharov2006_5-1) Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". *Astronomy Letters*. **32** (11): 759–771. [arXiv](/source/ArXiv_(identifier)):[1606.08053](https://arxiv.org/abs/1606.08053). [Bibcode](/source/Bibcode_(identifier)):[2006AstL...32..759G](https://ui.adsabs.harvard.edu/abs/2006AstL...32..759G). [doi](/source/Doi_(identifier)):[10.1134/S1063773706110065](https://doi.org/10.1134%2FS1063773706110065). [S2CID](/source/S2CID_(identifier)) [119231169](https://api.semanticscholar.org/CorpusID:119231169).

1. ^ [***a***](#cite_ref-Wang_6-0) [***b***](#cite_ref-Wang_6-1) [***c***](#cite_ref-Wang_6-2) [***d***](#cite_ref-Wang_6-3) Wang, Xiaoli; Ren, Shulin; Fu, Yanning (2015). ["Self-Consistent Orbits and Physical Properties for Eight Single-Lined Spectroscopic Binaries"](https://doi.org/10.1088%2F0004-6256%2F150%2F4%2F110). *The Astronomical Journal*. **150** (4): 110. [Bibcode](/source/Bibcode_(identifier)):[2015AJ....150..110W](https://ui.adsabs.harvard.edu/abs/2015AJ....150..110W). [doi](/source/Doi_(identifier)):[10.1088/0004-6256/150/4/110](https://doi.org/10.1088%2F0004-6256%2F150%2F4%2F110).

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 [19 Draconis](https://en.wikipedia.org/wiki/19_Draconis) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/19_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.