Identification of false positive double-lined spectroscopic binaries in LAMOST-MRS data due to moonlight contamination

ABSTRACT We present a method for identifying false positive double-lined spectroscopic binary (SB2) candidates by analysing medium-resolution survey spectra from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) DR10. Specifically, we focus on spectra contaminated by moonlight, which exhibit near-zero radial velocity (RV) and solar-like spectral lines from the secondary component. By applying strict constraints on the contamination parameters and fitting the contaminated spectra, we ultimately confirmed that 126 false positive binaries are single stars contaminated by moonlight. Additionally, we identify several key factors contributing to moonlight contamination: the lunar phase during observation, the G-band magnitude of the star, and the angular distance between the star and the moon. Notably, artificial satellites in low-orbital can also introduce contamination from solar-like spectral components, but they typically display significantly higher transverse velocities. In a follow-up study, we will expand our analysis to identify additional false positive SB2 systems and systematically classify them according to their contamination sources.