Low-mass emission-line stars belong to various evolutionary stages,from pre-main-sequence young stars to evolved stars.In this work,we present a catalog of late-type(F0 to M9)emission-line stars from the LAMOST Data R...Low-mass emission-line stars belong to various evolutionary stages,from pre-main-sequence young stars to evolved stars.In this work,we present a catalog of late-type(F0 to M9)emission-line stars from the LAMOST Data Release 6.Using the scipy package,we created a Python code that finds the emission peak at Hαin all latetype stellar spectra.A data set of 38,152 late-type emission-line stars was obtained after a rigorous examination of the photometric quality flags and the signal-to-noise ratio of the spectra.Adopting well-known photometric and spectroscopic methods,we classified our sample into 438 infrared(IR)excess sources,4669 post-main-sequence candidates,9718 Fe/Ge/Ke sources,and 23,264 d Me sources.From a crossmatch with known databases,we found that 29,222 sources,comprising 65 IR excess sources,7899 Fe/Ge/Ke stars,17,533 dMe stars,and3725 PtMS candidates,are new detections.We measured the equivalent width of the major emission lines observed in the spectra of our sample of emission-line stars.Furthermore,the trend observed in the line strengths of major emission lines over the entire late-type spectral range is analyzed.We further classified the sample into four groups based on the presence of hydrogen and calcium emission lines.This work presents a large data set of late-type emission-line stars,which can be used to study active phenomena in late-type stars.展开更多
文摘Low-mass emission-line stars belong to various evolutionary stages,from pre-main-sequence young stars to evolved stars.In this work,we present a catalog of late-type(F0 to M9)emission-line stars from the LAMOST Data Release 6.Using the scipy package,we created a Python code that finds the emission peak at Hαin all latetype stellar spectra.A data set of 38,152 late-type emission-line stars was obtained after a rigorous examination of the photometric quality flags and the signal-to-noise ratio of the spectra.Adopting well-known photometric and spectroscopic methods,we classified our sample into 438 infrared(IR)excess sources,4669 post-main-sequence candidates,9718 Fe/Ge/Ke sources,and 23,264 d Me sources.From a crossmatch with known databases,we found that 29,222 sources,comprising 65 IR excess sources,7899 Fe/Ge/Ke stars,17,533 dMe stars,and3725 PtMS candidates,are new detections.We measured the equivalent width of the major emission lines observed in the spectra of our sample of emission-line stars.Furthermore,the trend observed in the line strengths of major emission lines over the entire late-type spectral range is analyzed.We further classified the sample into four groups based on the presence of hydrogen and calcium emission lines.This work presents a large data set of late-type emission-line stars,which can be used to study active phenomena in late-type stars.
