Astronomy:39 Draconis
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| 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 | |
| U−B color index | +0.06[4] |
| B−V color index | +0.10[4] |
| Astrometry | |
| Radial velocity (Rv) | −24.53±0.23[5] 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 |
| Distance | 184 ± 4 ly (56 ± 1 pc) |
| Absolute magnitude (MV) | 1.31 / 4.32[6] |
| 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 | |
| Mass | 2.12[6] M☉ |
| Radius | 2.3[7] R☉ |
| Surface gravity (log g) | 4.05 ± 0.07[7] cgs |
| Temperature | 8710[7] K |
| 39 Dra B | |
| Mass | 1.18[6] M☉ |
| Other designations | |
| Database references | |
| SIMBAD | 39 Dra |
| 39 Dra A | |
| 39 Dra B | |
39 Draconis is a wide binary star system in the northern circumpolar constellation of Draco. It has the Bayer designation b Draconis, while 39 Draconis is the Flamsteed designation. This system is visible to the naked eye as a dim, white-hued point of light with an apparent visual magnitude of 5.0.[2] Parallax measurements made by the Hipparcos spacecraft put it at a distance of 184 light-years, or 56 parsecs away from the Sun.[1] The system is moving closer to the Earth with a heliocentric radial velocity of -24.5 km/s.[5]
The two components of 39 Draconis have an angular separation of 6.621″ and take almost 4,000 years to orbit each other.[3] The primary star is an early A-type main-sequence star, having 2.12 times the mass of the Sun with a visual magnitude of 5.06[3] The secondary is a magnitude 8.07[3] F-type main-sequence star, and has 1.18 times the mass of the Sun.[6]
The 8th-magnitude star HD 238865 is listed in double star catalogues as component C.[8] It is separated from the other two stars by 90″ and lies at about the same distance.[9] It is itself a spectroscopic binary with an F8 primary and a red dwarf secondary orbiting every 2.7 days.[10][11]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. Bibcode: 2007A&A...474..653V. http://www.aanda.org/index.php?option=com_article&access=bibcode&Itemid=129&bibcode=2007A%2526A...474..653VFUL.
- ↑ 2.0 2.1 2.2 "* b Dra". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+b+Dra.
- ↑ 3.0 3.1 3.2 3.3 3.4 "Sixth Catalog of Orbits of Visual Binary Stars". United States Naval Observatory. http://www.usno.navy.mil/USNO/astrometry/optical-IR-prod/wds/orb6.
- ↑ 4.0 4.1 Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode: 1986EgUBV........0M. http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?1986EgUBV........0M&db_key=AST&nosetcookie=1.
- ↑ 5.0 5.1 Pourbaix, D. et al. (2004). "SB9: The ninth catalogue of spectroscopic binary orbits". Astronomy and Astrophysics 424 (2): 727–732. doi:10.1051/0004-6361:20041213. Bibcode: 2004A&A...424..727P.
- ↑ 6.0 6.1 6.2 6.3 Novakovic, B.; Todorovic, N. (2006). "Orbits of four double stars". Serbian Astronomical Journal 172 (172): 21. doi:10.2298/SAJ0672021N. Bibcode: 2006SerAJ.172...21N. http://pdfs.semanticscholar.org/bac6/e1d877f654e5188d0094bdd2e9cb9525ad39.pdf.
- ↑ 7.0 7.1 7.2 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.
- ↑ Mason, B. D. et al. (2014). "The Washington Visual Double Star Catalog". The Astronomical Journal 122 (6): 3466–3471. doi:10.1086/323920. Bibcode: 2001AJ....122.3466M.
- ↑ Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ De Rosa, R. J.; Patience, J.; Wilson, P. A.; Schneider, A.; Wiktorowicz, S. J.; Vigan, A.; Marois, C.; Song, I. et al. (2014). "The VAST Survey - III. The multiplicity of A-type stars within 75 pc". Monthly Notices of the Royal Astronomical Society 437 (2): 1216. doi:10.1093/mnras/stt1932. Bibcode: 2014MNRAS.437.1216D.
- ↑ Tokovinin, A. A.; Smekhov, M. G. (1995). "Spectroscopic components in multiple systems: ADS 11336C". Astronomy Letters 21 (2): 247. Bibcode: 1995AstL...21..247T.
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