A study of angular momentum change in the orbit of an eclipsing binary systemV1851 Orionis

Abstract

The aim of this research was to study the orbital periods and physical characteristics of binary star  V 1851 Orionis, a type W Uma eclipsing binary star system. It is changing the physical characteristics of a contact  binary star system to a semidetacted binary star system. The researchers therefore carried out a step-by-step research to analyze the new physical data using photometry techniques. by collecting data with reflecting telescope 0.7 m in diameter, connected to the CCD photometer system through the filters light in the blue (B), visible (V) and red (R) wavelengths according to the UVB standard system at the Nakhon Ratchasima Regional observatory for the public, collecting data between 18 - 21 November 2020 and during 22 - 23 December 2020. The result showed that the new linear ephemeris equation was HJD = 2452617.7356 + 0.27695E. The orbital period of the binary star system V 1851 Orionis increases at the rate of 5.02294198 × 10^-17 seconds per year,  when analyzing its physical characteristics using the PHOEBE program. It was found that the mass ratio was 0.64694, the angle of inclination of the orbital plane was 87.78448 degrees, the temperature of the primary star and the secondary star were 5,711 Kelvin and 6,000 Kelvin, respectively. The primary stars and secondary stars have the same mass 18.761285 and 12.137425 times the sun, respectively.  From the analysis of the data, it can be concluded that the binary star V 1851 Orionis is an eclipsing binary system of type W Uma, both of which are dwarf stars. It has spectral types exist in the G0 constellation and has an increased orbital period. It shows that the two stars of this binary system are moving apart. This is not in line with angualar momentum loss theory (AML) stellar evolution hypothesis.