Astronomers have discovered a system consisting of two similar mass red dwarf stars that revolve around each other in an unusually eccentric orbit. Researchers believe that the discovery will help better understand the fundamental properties of low-mass stars, Preprint available on the website arXiv.org.
Red dwarfs — the most common type of stars in our galaxy. Around them sometimes called exoplanets, some of which its parameters are similar to our Earth. However, in order to determine the characteristics of the planetary system, it is necessary to accurately know the parameters of the parent stars, and red dwarfs are still much worse studied than, for example, yellow dwarfs, like our Sun. So, their measured masses and radii can sometimes differ from the model predictions by 10 percent, and this directly affects the determination of the main parameters of the planets.
Of particular interest to astronomers represent zatmenie double star in which the plane of the orbits of celestial bodies close to the line of sight of the observer and the components periodically pass in front of each other. Due to this property, scientists can quite accurately measure the mass, radius and effective temperature of the stars.
A team of astronomers under the leadership of Jack Acton (Acton Jack S.) from the University of Leicester has discovered one such eclipsing binary stars. System, open the survey the Next Generation Transit Survey and called NGTS J214358.5-380102, is 390 light years from Earth. It consists of two nearly identical red dwarfs: the radius of the main component is about 0,46 solar and a weight of 0.42 solar masses, while the radius and the mass of the secondary component are of 0.41 and 0.45 solar, respectively. One revolution around a common center of mass of a star do for the 7.62 days.
It turned out that the orbit of the stars is quite extended: the value of its eccentricity is 0,323. It is unusual for a double of red dwarfs, as usually they move in orbits that are close to circular. Moreover, it was found that NGTS J214358.5-380102 in principle has the highest eccentricity among the double red dwarfs and one of the highest eccentricities among the double stars in General (relative to the semimajor axis of the orbit, which is 15.6 astronomical units).
Astronomers are not sure what caused abnormal elongation of the orbits of stars. One scenario assumes that the high eccentricity and relatively short period of NGTS J2143-38 may indicate the presence of a third component in the system. Future observations will help test this theory.
Last year, scientists discovered an extremely close setmenu binary system of white dwarfs, the orbital period of which is of 6.91 minutes. This double star was the second in the list of most short-period and very close among the eclipsing systems.