VW LMi: tightest quadruple system known. Light-time effect and possible secular changes of orbits

• Published in: Monthly notices of the Royal Astronomical Society Vol. 390; no. 2; pp. 798 - 806
• Main Authors: Pribulla, T., Baluďanský, D., Dubovský, P., Kudzej, I., Parimucha, Š., Siwak, M., Vaňko, M.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 21.10.2008; Blackwell Science; Oxford University Press
• Subjects: Astronomy; Astrophysics; binaries: eclipsing; binaries: spectroscopic; Double stars; Earth, ocean, space; Exact sciences and technology; Orbits; Spectrum analysis; binaries: eclipsing; binaries: spectroscopic; Eclipsing binary stars; Photometric observation; Contact binary; Orbits; Nearby stars; Precession; Disturbances; Radial velocity; Spectroscopical observation; Detached binary; Spectroscopic binary stars
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1111/j.1365-2966.2008.13781.x

Tightest known quadruple system VW LMi consists of contact eclipsing binary with P12= 0.477 551 d and detached binary with P34= 7.930 63 d revolving in rather tight, 355.0-d orbit. This paper presents new photometric and spectroscopic observations yielding 69 times of minima and 36 disentangled radial velocities for the component stars. All available radial velocities and minima times are combined to better characterize the orbits and to derive absolute parameters of components. The total mass of the quadruple system was estimated at 4.56 M⊙. The detached, non-eclipsing binary with orbital period P= 7.93 d is found to show apsidal motion with U≈ 80 yr. Precession period in this binary, caused by the gravitational perturbation of the contact binary, is estimated to be about 120 yr. The wide mutual orbit and orbit of the non-eclipsing pair are found to be close to coplanarity, preventing any changes of the inclination angle of the non-eclipsing orbit and excluding occurrence of the second system of eclipses in future. Possibilities of astrometric solution and direct resolving of the wide, mutual orbit are discussed. Nearby star, HD 95606, was found to form loose binary with quadruple system VW LMi.