Eight new 2+2 doubly eclipsing quadruple systems detected

¹ Charles University, Faculty of Mathematics and Physics, Astronomical Institute, V Holešovičkách 2, 180 00 Praha 8, Czech Republic
e-mail: zasche@sirrah.troja.mff.cuni.cz
² Hvězdárna Jaroslava Trnky ve Slaném, Nosačická 1713, Slaný 1 274 01, Czech Republic
³ Variable Star and Exoplanet Section, Czech Astronomical Society, Fričova 298, 251 65 Ondřejov, Czech Republic
⁴ Astronomical Institute, Academy of Sciences, Fričova 298, 251 65 Ondřejov, Czech Republic
⁵ Research Centre for Theoretical Physics and Astrophysics, Institute of Physics, Silesian University in Opava, Bezručovo nám. 13, 746 01 Opava, Czech Republic

Received: 16 April 2024
Accepted: 9 May 2024

Abstract

We studied eight new doubly eclipsing stellar systems. We found that they are all rare examples of quadruple systems of 2 + 2 architecture, where both inner pairs are eclipsing binaries. Until now, such a configuration had only been proven for dozens of systems on the whole sky. We enlarged this rare group of systems with four stars in the Small Magellanic Cloud (SMC) galaxy and four brighter stars on the northern sky. These analysed systems are the following: OGLE SMC-ECL-2339 (both eclipsing periods of 0.72884 days and 3.39576 days; mutual orbital period of 5.95 years); OGLE SMC-ECL-3075 (1.35890 d, 2.41587 d, 9.75 yr); OGLE SMC-ECL-4756 (0.91773 d, 2.06047 d, 4.34 yr); OGLE SMC-ECL-6093 (0.90193 d, 2.03033 d, 31.2 yr); GSC 01949-01700 (0.24058 d, 0.75834 d, 21.7 yr); ZTF J171602.61+273606.5 (0.36001 d, 4.51545 d, 19.5 yr); WISE J210935.8+390501 (0.33228 d, 3.51575 d, 1.9 yr); and V597 And (0.46770 d, 0.35250, 20.4 yr). These systems constitute a rare selection of W UMa stars among the doubly eclipsing quadruples. For all of the systems, new dedicated observations were obtained as well. V597 And is definitely the most interesting system for several reasons: (1) the system is the brightest in our sample; (2) it is a rare quintuple (2 + 2) + 1 system; and (3) it is also closest to the Sun. It yielded the predicted angular separation of the two components of 57 mas, which is probably within the detection limits for modern, high-angular-resolution techniques.