Data Mining for WDMS in SDSS DR12 Archive

Data Release 12 is the final data release of the SDSS-III, containing all SDSS observations. The massive spectra can not only be used for research of the structure and evolution of the Galaxy but also for multi-waveband identification. In addition, the spectra are a ideal sample for data mining for rare and special objects like white dwarf main-sequence star. WDMS consists of a white dwarf primary and a low-mass main-sequence companion which has positive significance to the study of evolution and parameters of close binaries. In this paper, after feature extraction by PCA, an clustering approach is proposed based on the idea that cluster centers are characterized by a higher density than their neighbors and by a relatively large distance from points with higher densities. A total number of 2,340 WDMS candidates are selected by the method and some of them are new discoveries which prove that our approach of finding special celestial bodies in massive spectra data is feasible.