Higher-order multiple star systems, which include binaries and systems with more than two stars, are fascinating for several reasons and are of considerable importance in astrophysics.

Quadruple star systems with two mutually orbiting eclipsing pairs (2+2 quadruple systems) can be schematically represented as shown in the figure.

Their light curve may seem complicated at first glance, but our primary task is to separate the light curves from each other and determine the period of pair A and pair B.

Understanding star formation: Observing these systems helps astronomers study the processes of star formation. Multiple star systems can provide clues about how stars form in clusters and what the dynamics are in their early stages of development.

Star evolution: Interactions between stars in multiple systems can affect their evolutionary paths. For example, mass transfer in close binary systems can change the life cycles of the stars involved, leading to phenomena such as mass exchange or even stellar mergers.

Gravitational dynamics: These systems serve as excellent natural laboratories for studying gravitational dynamics and astrophysical processes. By studying their orbits and gravitational interactions, scientists can test theories of gravity and mechanics under a variety of conditions.

Unique phenomena: Multiple star systems can give rise to unique phenomena such as eclipsing binaries and variable stars. These occurrences produce changes in brightness that can be studied to infer properties of the stars, such as their mass, radius, and distance from Earth.

Jakub Kolář, leader SQUADRA project

Miloslav Zejda, active observer

Jan Janík, spectroscopy expert

Reinhold Friedrich Auer, observer

Petr Dvořák, observer

Radek Dřevěný, observer

Milan Uhlár, observer

Anna Richterková, student

Prokop Ohlídal, student

Sabina Pačková, student

Jakub Vyskočil, student

The Squadra group has observation equipment Masaryk University, Observatory and Planetarium in Brno and also has its own sets:

Helios 2/58 + G2-402, Nová Ves/Brno, CZ

D400 - G2-0400 BVRI - C, Prostějov, CZ

NWT 200f4 - G2-1600 BVRI-C, Veverska Bityska, CZ

Nikkor 180 f2.0 + G2-4000, Lajatico, IT

NWT 300/f4 - G2-1600 BVRI-C, Lajatico, IT

NWT 200/f4 - CMOS C2 7000A+ Sloan G,R,I - Clear, Znojmo, CZ

CARL ZEISS 200/2.8 + QHY 294 Pro Mono, Jirny, CZ

Period ratios and observation of noticeable resonance at 3:2 for 2+2 quadruple systems
KOLÁŘ, Jakub, Miloslav ZEJDA, Anna RICHTERKOVÁ, Petr DVOŘÁK, Reinhold Friedrich AUER, Zbyněk HENZL, Radek DŘEVĚNÝ, Sabina PAČKOVÁ a Milan UHLÁR. Period ratios and observation of noticeable resonance at 3:2 for 2+2 quadruple systems. Monthly Notices of the Royal Astronomical Society. Oxford University Press, 2025, roč. 538, č. 2, s. 1160-1166. ISSN 0035-8711.

Study of a selected multiple eclipsing system - quadruple star Brh V154, Anna Richterková.

Photometric analysis of multiply eclipsing systems, Sabina Pačková.