Spectroscopic Analysis of Compact Binary Candidate LAMOST J051402.68+172659.7
WANG Qi1, YANG Hai-feng2*, CAI Jiang-hui3*
1. School of Mathematics and Information Technology, Yuncheng University, Yuncheng 044000, China
2. School of Computer Science and Technology, Taiyuan University of Science and Technology, Taiyuan 030024, China
3. School of Computer Science and Technology, North University of China, Taiyuan 030051, China
Abstract：Compact binary systems usually have faster orbital motion, more frequent light variation effects, and the rapid evolution of companion stars, so they are important for studying interstellar physical processes and stellar evolution. Photometric images and light curves are the most common approaches to identifying binary stars. Suppose the current observation technology cannot distinguish binary objects' brightness and position difference. In that case, the spectral type is also one of the important methods used to distinguish the composition of the companion star. This paper uses the spectral binary star analysis method based on a rough set and cluster voting mechanism to analyze the spectral characteristics and identify the outlier LAMOST J051402.68+172659.7. First, for the spectral binary stars (DoubleStar) released by LAMOST DR10, human inspecting was conducted on the 17 target spectra with the lowest number of votes in its multiple clustering results. In addition to the low signal-to-noise ratio of most spectra, the two observed spectra of LAMOST J051402.68+172659.7 show great difference; For the two observations of the target, its spectrum once presents F-type and once presents F+M type. After excluding the pollution of neighboring optical fibers and other targets in the target's environment, it is determined that the real components of the target are displayed in the two observation spectra, indicating that the two spectral components come from two stellar targets. The radial velocity difference between the two observations is about 20.3 km·s-1, and the observation interval is 3 days, indicating that the rotation period is less than 6 days. Considering that the conditions for the simultaneous occurrence of multiple target components in the same spectrum are extremely strict, the spectral types are very different, and the luminance (flow) is on the same scale, the spectral components, imaging, and light variation are analyzed in depth in this paper. From the image sequence of ZTF photometry, it can be detected that the size of the target contour presents periodic changes. In contrast, no obvious periodic changes are found on the light curve of ASAS-SN and ZTF. At the same time, because the distance between the two celestial bodies is very close or the projection is covered, the characteristics of the point source (the boundary is slightly irregular) cannot be identified from the SDSS and 2MASS spectrophotometry images, so the orbit between the two stars of the binary star system may be relatively close and the radius is small. Balmer weak emission lines (Hα, Hβ, Hγ, Hδ) and forbidden lines ([NII]λ6550, [SII]λλ6718, 6733, [OII]λ3728) are present in its spectrum, and the target is not in the planetary nebula or HII region, which is speculated to be the tidal effect and material exchange caused by the interaction of companion stars. This impacts the star's surface and atmosphere, creating emission lines. In addition, the target spectrum also shows extremely weak emission line components of suspected background galaxies, which cannot be distinguished from imaging and are presumed to be data processing remnants.
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