2020/01/23 by Andrei Tokovinin, Andreï Tokovinin · 4 citations
Chemistry · Physics and Astronomy · #Astro and Planetary Science #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Binary number #Binary star #Binary system #Chemistry #Eccentricity (behavior) #Flux (metallurgy) #Geometry #Line (geometry) #Orbital eccentricity #Orbital period #Parallax #Physics #Radial velocity #Stars #Starspot #Stellar, planetary, and galactic studies #astro-ph.EP #astro-ph.SR
paper · pdf · doi:10.3847/1538-3881/ab6a13
published in The Astronomical Journal 159(3), 88 (Institute of Physics) · Accepted by Astronomical Journal; 9 pages, 8 figures, 8 tables
arxiv created 2020/01/23 · openalex publication_date 2020/02/05 · arxiv updated 2021/01/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Abstract HIP 45734 is a quadruple system of 2 + 2 architecture located at 68 pc from the Sun. The outer 9″ system A,B has a period of ∼10 4 yr. The subsystem Aa,Ab is a visual binary with a period of 20.1 yr and an eccentricity of 0.78. Its periastron in 2019.1 was observed spectroscopically, yielding masses (1.10 ± 0.04 and 0.98 ± 0.03 <?CDATA \mathcal M \odot ?> ) and orbital parallax, 14.90 ± 0.37 mas. The masses, luminosities, and colors approximately agree with evolutionary models of main-sequence stars. Component Aa has a detectable lithium line, whereas in Ab it is absent. The pair Ba,Bb is a single-lined spectroscopic binary with a period of 0.55552 day and an orbital inclination of ∼45° derived by modeling the rotationally broadened line profile with flat bottom. The mass of Bb is ∼0.4 <?CDATA \mathcal M \odot ?> . Star B is chromospherically active (an X-ray source); its flux is modulated with the orbital period by starspots, in addition to occasional flares. The system is probably older than ∼600 Myr; it does not belong to any known moving group.