Subjects: Astronomy submitted time 2024-03-26 Cooperative journals: 《天文学进展》
Abstract： White dwarfs are the degenerate stellar cores remaining at the end of the evo#2;lution of low- and median-mass stars, which represent the final fate of more than 97% of the celestial bodies in the Milky Way. White dwarfs contain the information of stars from birth to death, which can be used to constrain the theory of stellar evolution, such as the mass loss rate in the post-AGB stage at the end of stellar evolution, which also directly affects the initial-final mass relation of stars. White dwarfs may arise from the evolution of multiple star systems. It is estimated that 25% ∼ 30% of white dwarfs are the outcome of binary or multiple star mergers, and white dwarfs with a mass less than 0.4 M⊙ are generally considered to be the result of binary evolution. Therefore, white dwarfs can be used to verify the binary star evolution theory. The white dwarf cooling sequence provides an independent cosmic clock to constrain the ages of the various stellar populations in the Milky Way. Since the white dwarf population contain information about the formation his#2;tory and evolution of the Milky Way, and the study of the properties of the white dwarf population requires a large number of well-defined white dwarf samples. Combining Gaia’s high-precision photometry and annual parallax data, we searched for white dwarfs in the low-resolution spectroscopic data of the eighth data release (DR8) of LAMOST. By using the method of template matching, a total of 4 692 white dwarfs and 85 cataclysmic variables were found in LAMOST DR8, among which 2 876 objects were proved to be white dwarfs in the previous work, and 1 854 objects were white dwarfs discovered in LAMOST for the first time. After visual confirmation, we carried out a detailed classification of the white dwarf spectral types. After comparison, the completeness of the white dwarf sample is 80%, and the accuracy of classification is 99%. The final LAMOST white dwarf sample can well reflect the distribution of different types of white dwarfs on the Gaia CMD map.
Subjects: Astronomy submitted time 2024-03-22 Cooperative journals: 《天文学进展》
Abstract： White dwarfs are the degenerate stellar cores remaining at the end of the evo#2;lution of low- and median-mass stars, which represent the final fate of more than 97% of the celestial bodies in the Milky Way. White dwarfs contain the information of stars from birth to death, which can be used to constrain the theory of stellar evolution, such as the mass loss rate in the post-AGB stage at the end of stellar evolution, which also directly affects the initial-final mass relation of stars. White dwarfs may arise from the evolution of multiple star systems. It is estimated that 25% ∼ 30% of white dwarfs are the outcome of binary or multiple star mergers, and white dwarfs with a mass less than 0.4 M⊙ are generally considered to be the result of binary evolution. Therefore, white dwarfs can be used to verify the binary star evolution theory. The white dwarf cooling sequence provides an independent cosmic clock to constrain the ages of the various stellar populations in the Milky Way. Since the white dwarf population contain information about the formation his#2;tory and evolution of the Milky Way, and the study of the properties of the white dwarf population requires a large number of well-defined white dwarf samples. Combining Gaia’s high-precision photometry and annual parallax data, we searched for white dwarfs in the low-resolution spectroscopic data of the eighth data release (DR8) of LAMOST. By using the method of template matching, a total of 4 692 white dwarfs and 85 cataclysmic variables were found in LAMOST DR8, among which 2 876 objects were proved to be white dwarfs in the previous work, and 1 854 objects were white dwarfs discovered in LAMOST for the first time. After visual confirmation, we carried out a detailed classification of the white dwarf spectral types. After comparison, the completeness of the white dwarf sample is 80%, and the accuracy of classification is 99%. The final LAMOST white dwarf sample can well reflect the distribution of different types of white dwarfs on the Gaia CMD map.
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