19 Draconis

Star in the constellation Draco Draco constellation map.svg center 280 right Red circle.svg 10 19 Dra 436 704 Location of 19 Dra (circled in red) J2000 Draco 16 56 01.68925Validation of the new Hipparcos reduction http://www.aanda.org/index.php?option=com_article&access=bibcode&Itemid=129&bibcode=2007A%2526A...474..653VFUL van Leeuwen, F. etal Astronomy and Astrophysics 474 2 653–664 2007 0708.1752 2007A&A...474..653V 10.1051/0004-6361:20078357 free 18759600 +65 08 05.2631 4.89 main sequence1635375460142367104 F8VAbt, Helmut A. 2009 MK Classifications of Spectroscopic Binaries The Astrophysical Journal Supplement 180 1 117–18 10.1088/0067-0049/180/1/117 2009ApJS..180..117A 122811461 +0.485Mermilliod, J.-C. Compilation of Eggen's UBV data, transformed to UBV (unpublished) Catalogue of Eggen's UBV Data http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?1986EgUBV........0M&db_key=AST&nosetcookie=1 1986 1986EgUBV........0M -0.03 −21.00 ± 0.8Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system Gontcharov, G. A. 2006 Astronomy Letters 32 11 759–771 2006AstL...32..759G 10.1134/S1063773706110065 1606.08053 119231169 237.79 50.84 65.54 0.33 3.98 2015AJ....150..110W 10.1088/0004-6256/150/4/110 Self-Consistent Orbits and Physical Properties for Eight Single-Lined Spectroscopic Binaries The Astronomical Journal 150 4 110 2015 Wang Xiaoli Ren Shulin Fu Yanning free 52.1089 ± 0.0001 d 20.0 mas 90.5 ± 2.2 23.5 ± 2.0 JD 2453427.880 ± 0.007 0.2221 ± 0.0002 338.46 ± 0.05 17.465 ± 0.004 19 Dra A 1.04 1.2 6298 ± 80 2.02 Z 0.013 ± 0.004 4.7 19 Dra B 0.37 ~3963From L = 4πR2σTeff4, rearranging to make Teff = (L / 4πR2σ)1/4. Where L is the luminosity, R is the radius, Teff is the effective surface temperature and σ is the Stefan–Boltzmann constant. 0.02 0.3 +65°1157 648 153597 82860 6315 17281 19+Dra 01349 thumb|left|19 Draconis in optical light 19 Draconis, also known as h Draconis, is a star system in the constellation Draco. It is visible to the naked eye as a faint, yellow-white hued star with an apparent visual magnitude of 4.89. Based on its parallax, the system is located about 49.8 light-years (15.26 parsecs) away. It is moving closer to the Earth with a heliocentric radial velocity of −21 km/s. This is a binary star system with an orbital period of 52.1 days and an eccentricity of 0.22. Only the primary star can be directly detected, via Doppler shifts or perturbations 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 with a stellar classification of F8V, 4% more massive than the Sun. Its surface temperature is about 6,298 K, and it emits just over twice the amount of energy that the Sun does. The secondary is only 37% as massive as the Sun, and its luminosity is only 2% that of the Sun. The system is about 4.7 billion years old. Notes note References Category:Solar-type stars Category:Spectroscopic binaries Category:Draco (constellation) Draconis, h Category:Durchmusterung objects Draconis, 19 0648 153597 082860 6315 Category:F8V stars