(ORDO NEWS) — Astronomers have discovered the first system of three eclipsing binary stars. As reported in a preprint available at arxiv.org, the TIC 168789840 system can help researchers understand how such objects are formed.
If nearby binary stars, orbiting a common center of mass, close each other, they are called eclipsing binaries. This is possible in the case when the plane of the orbit of the stars is close to the line of sight of the observer. Double eclipsing stars are rare, with only 150 such objects known to scientists in 2019. Eclipsing systems with a large number of luminaries are observed even less often – for example, only the third system, consisting of two eclipsing binary stars, was recently discovered.
Brian Powell of NASA’s Goddard Space Flight Center and his colleagues analyzed data from the TESS telescope. First, astronomers selected from the catalog all the stars with a magnitude of 15 and above, and then using a neural network analyzed their light curves in search of systems consisting of two or more objects.
As a result, they managed to discover the first system that includes three eclipsing binary stars – TIC 168789840 located at a distance of about 1.9 thousand light years. Two pairs, A and C, which are made up of eclipsing binaries that orbit a common center of mass in 1.57 and 1.3 days, respectively, make one complete revolution around each other in 3.7 years. Another eclipsing binary star, B, consists of stars orbiting each other with a period of 8.2 days and makes one revolution around the pair A and C in two thousand years.
Although TIC 168789840 is not the first known six-star system, it is the first system where all stars eclipse each other. According to astrophysicists, A and C were once a young binary star, past which a third single star B passed.This led to its gravitational capture, and also caused disturbances in the surrounding gas and dust cloud, as a result of which companions were generated for each of the components of the triple system … This hypothesis may be supported by the fact that in each binary system, the mass of one star is close to 1.3 solar, and the mass of the second star is about half that.
In future observations, astronomers hope to find out if the intermediate and outer orbital planes are aligned with the planes of the three eclipsing binaries (that is, planes A and C and planes AC and B). Objects like these can help scientists understand how systems that include multiple stars are born and evolve.
The existence of the first system of five stars was confirmed only in 2015 – it is located in the constellation Ursa Major. In addition, scientists have recently discovered a third exoplanet in the Kepler-47 binary star system.
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