Physical characterization of late-type contact binary systems observed by LAMOST: a comprehensive statistical analysis.

This paper presents a catalog of approximately 1800 Eclipsing W UMa systems (EWs) using parameters from LAMOST, VSX, ZTF and Gaia. Our detailed statistical analysis includes frequency distributions of parameters, confidence intervals, and hypothesis testing to provide deeper insights into the physical properties of this important eclipsing binary class. We focus on key parameters, including Period, Effective Temperature, Surface Gravity, metallicity, Radial Velocity, and spectral type of the systems. Our study reveals that the mean values for period, effective temperature, logarithmic surface gravity, metallicity, and radial velocity for EW systems are 0.377 days, 5775 K, 4, -0.185, and -4.085 km/s, respectively. The 95% confidence intervals for these parameters are 0.372 to 0.382 days, 5730 to 5820 K, -0.202 to -0.168, 3.97 to 4.03, and -6.47 to -1.7 km/s, respectively. Hypothesis testing of the estimated intervals results in the acceptance of the null hypothesis, indicating that EW systems are characterized within the specified limits. Our study also confirms that the majority of EW systems are late-type stars, primarily classified as F spectral type, followed by G and K. Interestingly, among the sample, 88 systems are classified as A spectral type, with a mean surface temperature of 7400 K. We examine the correlation between orbital periods and atmospheric parameters in the VSX and ZTF catalogs. While ZTF periods align well with established relations (correlation coefficient: 0.74), a weaker correlation is found in the VSX catalog. This highlights the need for a revision of VSX periods for improved accuracy in the studied sample of EWs.