Russia: Astronomers discover a unique binary star with a rare orbital cycle

Russian astronomers have recorded the discovery of a rare eclipsing variable star in the constellation Pegasus, which received the designation Grigoriev 1. The discovery of the object was part of a long-term scientific program aimed at studying variable stars and supernovae, in which 120 such objects have already been registered so far. Grigoriev 1 stands out among them as one of the most unusual and promising for further research.

The star was discovered based on an analysis of data collected in the ultraviolet range using the GALEX Space Observatory. The identified object is an eclipsing binary system with an orbital period of about 6.6 days. The duration of each eclipse is about 1.5 hours, with partial phases occurring thirty times faster than the main phase of the eclipse.

Measurements in various spectral filters revealed significant brightness fluctuations: gin the filter, the luminosity drops by two magnitudes, which is equivalent to a 6.3-fold decrease in brightness, and in the r- filter — by 1.4 magnitude (3.6 times). These differences in the depth of eclipses indicate a noticeable temperature and light asymmetry of the system's components.

Analysis of observational data revealed that one of the system's components — the eclipsing object, is about 30 times the size of its companion and five times brighter, despite the lower temperature. Calculated estimates show that the radius of the cold component reaches 323,500 km, while the radius of its satellite is about 10,000 km. The orbital radius of the star pair is approximately 0.069 astronomical units.

Astrophysicists have classified the system as an analog of binary systems like Algol-interacting stellar pairs, where one of the objects transfers mass to the other through the so-called Roche cavity. In the case of Grigoriev 1, a unique configuration is observed: the white dwarf visible by the "edge" interacts with its companion, which is at the stage of an evolutionary transition. From the point of view of the color-luminosity diagram, the hot component occupies an intermediate position between white dwarfs and hot sub-dwarfs, which makes the system particularly important for further studying the evolution of stellar remnants.

Based on the current classification data, Grigoriev 1 It is one of the Algol-type systems with one of the longest orbital periods known to modern science. This discovery opens up new horizons for theoretical models of the evolution of binary stars and refinement of mass transfer parameters in compact systems.