12 Aquarii

Star system in the constellation Aquarius J2000 Aquarius 21 04 04.72438 -05 49 23.0347 5.67 (5.88 + 7.55) K0/1 III + A3 V or G4 II + A3+ + (A4) +1.1 0.3 +20.35 -6.67 6.50 0.88 0.1 + 1.4 + 1.5 12 Aqr Aa/Ab 2.6/2.0 5,012/8,511 12 Aqr B 1.9 8,318 12 Aqr -06°5664 103981 J21041-0549AB 14592 J21041-0549AB 12 Aqr A 200497 8059 145065 12 Aqr B 200496 8058 145064 HIP+103981 12 Aqr 12+Aqr+A 12 Aqr A 12+Aqr+B 12 Aqr B 12 Aquarii is a triple star system in the zodiac constellation of Aquarius. 12 Aquarii is the Flamsteed designation. It is visible to the naked eye as a dim star with an apparent visual magnitude of 5.67. Parallax measurements by Hipparcos puts it at a distance of some 500 light-years, or 150 parsecs away. The system is moving further from the Earth with a heliocentric radial velocity of +1.1 km/s. The magnitude 5.88 primary, component A, is itself a binary star with a separation of 0.05 arcsecond–0.07 arcsecond and an orbital period of around 6760 days years out. The brighter member of this duo is a G-type bright giant with a stellar classification of G4 II and 2.6 times the mass of the Sun. Its companion is an early A-type star with double the mass of the Sun. The tertiary component B is magnitude 7.55 A-type main-sequence star at a separation of 2.44 arcsecond from the primary. References Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars 5 1999 Michigan Spectral Survey Houk N. Swift C. 1999MSS...C05....0H Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system Gontcharov G. A. Astronomy Letters 32 11 759–771 2006 2006AstL...32..759G 1606.08053 10.1134/S1063773706110065 119231169 Validation of the new Hipparcos reduction van Leeuwen F. Astronomy and Astrophysics 474 2 653–664 2007 0708.1752 2007A&A...474..653V 10.1051/0004-6361:20078357 18759600 . Eggleton P. P. Tokovinin A. A. A catalogue of multiplicity among bright stellar systems Monthly Notices of the Royal Astronomical Society 389 2 869–879 September 2008 10.1111/j.1365-2966.2008.13596.x free 0806.2878 2008MNRAS.389..869E 14878976 . New and Confirmed Triple Systems with Luminous Cool Primaries and Hot Companions Parsons Sidney B. The Astronomical Journal . 127 5 2915–2930 May 2004 10.1086/383546 2004AJ....127.2915P free Category:G-type bright giants Category:K-type giants Category:A-type main-sequence stars Category:Triple stars Category:Aquarius (constellation) Category:Durchmusterung objects Aquarii, 012 200496 7 103981 8058 9