Three new 2+2 quadruple systems with changing inclination

ABSTRACT We present a unique discovery of three new detected systems showing two different phenomena together. These are 2+2 quadruple stellar systems showing two eclipsing binaries as the inner pairs. And besides that, these systems were also found to exhibit the precession of the inner orbits causing the inclination changes manifesting themselves through the eclipse depth variations. We are not aware of any similar known system on the sky nowadays, hence our discovery is really unique. In particular these systems are: CzeV4315 = HD 228777 (periods 6.7391 and 0.91932 d, inclination change of pair B of about 1.4$^{\circ }$ yr−1); ASASSN-V J075203.23−323102.7 = GDS_J0752031−323102 (8.86916 d + 2.6817 d, inclination change of pair B of about 1.03$^\circ$ yr−1, now only ellipsoidal variations); ASASSN-V J105824.33−611347.6 = TIC 465899856 (2.3304 d + 13.0033 d, inclination change of pair B, now undetectable). These systems provide us unique insight into the quadruple-star dynamics, including the orbit–orbit interaction, Kozai–Lidov cycles, and testing the stellar formation theories of these higher order multiples.