The Physical Properties of Four Double-lined Detached Eclipsing Binaries with Similar Components and Third Bodies from the LAMOST Medium-resolution Survey

Abstract The stellar model is still facing challenges in explaining the origin of low-mass stars and brown dwarfs. Double-lined detached eclipsing binaries with low-mass and similar components play an important astrophysical role in accurately deriving fundamental parameters, investigating stellar properties, and restricting theoretical stellar models of low-mass stars. Using high-precision light curves and Large Sky Area Multi-Object Fiber Spectroscopic Telescope spectra, we first obtained the fundamental parameters of the four detached binaries (NSVS 07453183, V644 Aur, V912 Per, and V1250 Tau). Except for V1250 Tau ( q sp ∼ 0.95), the mass ratios of the other three targets are almost equal to 1, which is consistent with the core fragmentation and dynamical capture theories of binary formation. The O − C curves of these systems based on current data exhibit cyclic variations, which is due to the light-travel time effect caused by the presence of a third body. Among them, the third body of V912 Per is likely to be a stellar black hole <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo stretchy="false">(</mml:mo> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>3</mml:mn> </mml:mrow> </mml:msub> <mml:mi>sin</mml:mi> <mml:msub> <mml:mrow> <mml:mi>i</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>3</mml:mn> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>12.57</mml:mn> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>⊙</mml:mo> </mml:mrow> </mml:msub> <mml:mo stretchy="false">)</mml:mo> </mml:math> . The O − C diagram of NSVS 07453183 shows double-cycle oscillations, which means that it is perhaps a quadruple system. The third body of NSVS 07453183 is an M3-type main-sequence star based on third light analysis, and the fourth body maybe a brown dwarf. The obtained Hertzsprung–Russell diagram based on the Modules for Experiments in Stellar Astrophysics code suggested that the components of these four targets are main-sequence stars. These four targets will gradually form Algol-type binaries in the future, which are important systems for studying the reversal of the mass ratio.