13 Ceti

Star in the constellation Cetus 250px A light curve for BU Ceti, plotted from TESS data J2000.0 Cetus 00 35 14.87968 −03 35 34.2367 5.20 (5.61 + 6.90) 0.567 0.008 y A Main sequence + main sequence F6 V + K3.5 V RS CVn B Main sequence G4 V +10.37 0.40 +408.34 −35.22 47.05 0.67 3.56 A B 6.8975 0.0005 0.0006 234.07 0.74 0.73 mas 0.7615 0.0013 0.0014 none 1890.6139 0.0091 0.0085 47.83 0.24 104.70 0.18 328.39 0.22 11.68 0.51 15.59 0.17 Aa Ab 2.081891 0.000005 days commas 1.260 0.010 Mm ≥ 0.0 (fixed) 2443400.4573 0.0032 HJD commas 0.0 43.98 0.39 Aa 1.18 0.09 2.63 6,457 3.8 1.8 0.3 Ab 0.35 y B 0.90 0.09 0.83 5,754 2.5 BU Cet HO 212 13 Cet −04°62 23 3196 2762 142 128839 00352-0336 696 13+Cet 13 Ceti is a triple star system in the equatorial constellation of Cetus. It is dimly visible to the naked eye with a combined apparent visual magnitude of 5.20. The system is located at a distance of approximately 69 light years from the Sun based on stellar parallax, and is drifting further away with a radial velocity of +10.4 km/s. It shares a common motion with the Hyades moving group, although it is too old to be a member. 1 , - S3 Aa, F6V 0 , ( PC 2.1 days 1 - ( ` - S4  Ab, K3.5V  0 ! PA 6.9 years 1 ` - S1 B, G4V Hierarchy of orbits in the 13 Ceti system This star was identified as a visual binary system by G. W. Hough in 1844 and given the identifier HO 212. The pair have an orbital period of 2516.6163 days years 1 out off and an eccentricity of 0.76. The brighter member, designated component A, is an F-type main-sequence star with a stellar classification of F6 V and a visual magnitude of 5.61. It appears to have an active chromosphere and is classified as an RS Canum Venaticorum variable with a variable star designation of BU Cet. The star was detected as a source of soft X-ray emission by EXOSAT. It has 18% more mass than the Sun and is estimated to be about four billion years old. In 1907, E. B. Frost discovered the primary is a spectroscopic binary, making this a triple star system. This is a double-lined spectroscopic binary with a period of 2.1 days and a circularized orbit. The companion signature was confirmed using the separated fringe packet technique with the CHARA array. It is most likely a K-type main-sequence star with a class of K3.5 V and 70% of the mass of the Sun. The secondary member of the visual binary, designated component B, is a G-type main-sequence star with a class of G4 V. It has 90% of the Sun's mass and a visual magnitude of 6.90. A distant visual companion to this system was detected by S. W. Burnham in 1877. Designated component C, this star is a background object of magnitude 12.50. As of 1999, it was located at an angular separation of 24.0 arcsecond from the primary along a position angle of 322°. 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Brocato Enzo Andrade Manuel Campo Pedro P. Monthly Notices of the Royal Astronomical Society 492 2 2709–2721 February 2020 2020MNRAS.492.2709P 10.1093/mnras/stz3616 free collapsed Category:F-type main-sequence stars Category:G-type main-sequence stars Category:K-type main-sequence stars Category:RS Canum Venaticorum variables Category:Triple stars Category:Spectroscopic binaries Category:Cetus (constellation) BD-04 0062 Ceti, 13 0023 003196 002762 0142 Ceti, BU Category:Visual binaries