39 Draconis

39 Draconis
Observation data
Epoch J2000      Equinox J2000
Constellation Draco
Right ascension 18h 23m 54.60641s[1]
Declination +58° 48′ 02.6446″[1]
Apparent magnitude (V) 5.034[2]
(5.06 + 8.07)[3]
Characteristics
Spectral type A1V + F5V[4]
U−B color index +0.06[5]
B−V color index +0.10[5]
Astrometry
Radial velocity (Rv)-24.53 ± 0.23[6] km/s
Proper motion (μ) RA: -37.82[1] mas/yr
Dec.: 61.60[1] mas/yr
Parallax (π)17.71 ± 0.35[1] mas
Distance184 ± 4 ly
(56 ± 1 pc)
Absolute magnitude (MV)1.31 / 4.32[7]
Orbit[3]
Period (P)3962.50 ± 209.26 yr
Semi-major axis (a)6.621 ± 0.325″
Eccentricity (e)0.553 ± 0.005
Inclination (i)107.7 ± 0.12°
Longitude of the node (Ω)179.9 ± 0.10°
Periastron epoch (T)5671.40 ± 12.08
Argument of periastron (ω)
(secondary)		128.0 ± 2.18°
Details
39 Dra A
Mass2.12[7] M☉
Radius2.3[8] R☉
Surface gravity (log g)4.05 ± 0.07[8] cgs
Temperature8710[8] K
39 Dra B
Mass1.18[7] M☉
Other designations
BD+58° 1809, HD 170073, HIP 90156, HR 6923, SAO 30949[2]
Database references
SIMBAD39 Dra
39 Dra A
39 Dra B

39 Draconis, also known as b Draconis, is a wide binary star in the constellation Draco. Its apparent magnitude is 5.034.[2] Parallax measurements made by the Hipparcos spacecraft put it at a distance of 184 light-years, or 56 parsecs away.[1]

The two components of 39 Draconis are separated by 6.621″ and take almost 4,000 years to orbit each other. The primary star is an early A-type main-sequence star, 2.12 times the mass of the Sun. The secondary star is an F-type main-sequence star, and is 1.18 times the mass of the Sun.[7]

References

  1. 1 2 3 4 5 6 van Leeuwen, F.; et al. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. Bibcode:2007A&A...474..653V. arXiv:0708.1752 Freely accessible. doi:10.1051/0004-6361:20078357.
  2. 1 2 3 "* b Dra". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 21 June 2017.
  3. 1 2 "Sixth Catalog of Orbits of Visual Binary Stars". United States Naval Observatory.
  4. ↑ Lutz, T. E.; Lutz, J. H. (1977). "Spectral classification and UBV photometry of bright visual double stars". The Astronomical Journal. 82: 431. Bibcode:1977AJ.....82..431L. doi:10.1086/112066.
  5. 1 2 Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV data. Bibcode:1986EgUBV........0M.
  6. ↑ Pourbaix, D.; et al. (2004). "SB9: The ninth catalogue of spectroscopic binary orbits". Astronomy and Astrophysics. 424 (2): 727. Bibcode:2004A&A...424..727P. arXiv:astro-ph/0406573 Freely accessible. doi:10.1051/0004-6361:20041213.
  7. 1 2 3 4 Novakovic, B.; Todorovic, N. (2006). "Orbits of four double stars". Serbian Astronomical Journal. 172 (172): 21. Bibcode:2006SerAJ.172...21N. doi:10.2298/SAJ0672021N.
  8. 1 2 3 Allende Prieto, C.; Lambert, D. L. (1999). "Fundamental parameters of nearby stars from the comparison with evolutionary calculations: masses, radii and effective temperatures". Astronomy and Astrophysics. 352: 555–562. Bibcode:1999A&A...352..555A. arXiv:astro-ph/9911002 Freely accessible.


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