A5004475205- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Astronomical Observations and Instrumentation
- Astrophysics and Star Formation Studies
- Gamma-ray bursts and supernovae
- High-pressure geophysics and materials
- Galaxies: Formation, Evolution, Phenomena
- Astro and Planetary Science
- Astrophysical Phenomena and Observations
- Nuclear Physics and Applications
Hebei Normal University
2021-2024
Abstract Carbon stars are excellent kinematic tracers of galaxies and play important roles in understanding the evolution Galaxy. Therefore, it is worthwhile to search for them a large number spectra. In this work, we build new carbon star catalog based on Large Sky Area Multi-Object Fiber Spectroscopy Telescope (LAMOST) DR7 The contains 4542 spectra 3546 stars, identified through line index near-infrared color–color diagrams. Through visual inspection spectra, further subclassify into 925...
Abstract In this work, we present a catalog of cataclysmic variables (CVs) identified from the sixth data release (DR6) Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). To single out CV spectra, introduce novel machine-learning algorithm called UMAP to screen total 169,509 H α emission and obtain classification accuracy over 99.6% cross-validation set. We then apply template-matching program PyHammer v2.0 LAMOST spectra optimal spectral type with metallicity, which help us...
Abstract Using 9943 OB-type stars from LAMOST DR7 in the solar neighborhood, we fit vertical stellar density profile with model including a single exponential distribution at different positions ( R , Φ). The distributions of scale heights and length show that young disk traced by is not axisymmetric. decreases versus azimuthal angle Φ, i.e., <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mn>1.14</mml:mn> </mml:mrow>...
Abstract We construct a new catalog of the blue horizontal-branch (BHB) stars from Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) DR5 data set, which contains 5355 + 81 BHB at high Galactic latitude (∣Glat∣ > 20°). combine spectral line indices with set Balmer profile selection criteria to identify stars. During process, we use index Ca ii K exclude metal-rich A-type dwarfs. obtain their atmospheric parameters by crossmatching our provided Xiang et al. The results show...
Abstract The measurements of masses and luminosities massive stars play an important role in understanding the formation evolution their host galaxies. In this work, we present measurement 2946 OB-type stars, including 78 O-type 2868 B-type based on stellar parameters (effective temperature, surface gravity, metallicity) Padova Trieste Stellar Evolution Code isochrones model. Our results show that median mass luminosity are 5.4 M ⊙ log( L / ) = 3.2 with relative errors 21.4% 71.1%,...
Abstract Blue horizontal-branch (BHB) stars are crucial for studying the structure of Galactic halo. Accurate atmospheric parameters BHB essential investigating formation and evolution Galaxy. In this work, a data-driven technique named Stellar Label Machine (SLAM) is used to estimate Large Sky Area Multi-Object Fiber Spectroscopic Telescope low-resolution spectra with set A-type theoretical as training data set. We add color indexes (( BP − G ), ( RP J H )) during process constrain stellar...
ABSTRACT We present a new method for selecting A-type supergiants (A-SGs hereafter) in the LAMOST DR5 data set using line indices, and identify 40 spectra of 30 A-SG candidates. Based on analysis absolute magnitude Gaia DR3, SIMBAD base, ZTF light variation data, spectral characteristics A-SGs, we classified candidates into 18 A-SGs 12 with different levels credibility. also subclassify types by human eyes find good consistency between our results those MKCLASS most them. The spatial...
In this work, we update the catalog of OB stars based on Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) data release 7 and modified selection criterion spectral line indices space. The new includes 37,778 spectra 27,643 stars, which 3827 are newly identified. subclasses obtained using automatic classification code MKCLASS. We find that star criteria can better improve completeness late B-type by analyzing their results given also identify 3006 Be-type or candidates...
Abstract In this work, we update the catalog of OB stars based on Large Sky Area Multi-Object Fiber Spectroscopic Telescope data release 7 and modify stars’ selection criteria in spectral line indices’ space. The new includes 37,778 spectra 27,643 stars, which 3827 are newly identified. subclasses obtained using automatic classification code MKCLASS. We find that modified star can better improve completeness late B-type by analyzing their results given also identify 3006 Be-type or...
We construct a new catalog of the blue horizontal-branch (BHB) stars from Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) DR5 dataset, which contains 5355+81 BHB at high Galactic latitude (($|Glat|>20^{\circ}$). combine spectral line indices with set Balmer profile selection criteria to identify stars. During process, we use index \ion{Ca}{2}\,K exclude metal-rich A-type dwarfs. obtain their atmospheric parameters by cross-matching our provided \citet{Xiang2022}. The...
The measurements of masses and luminosities massive stars play an important role in understanding the formation evolution their host galaxies. In this work, we present measurement 2,946 OB-type stars, including 78 O-type 2,868 B-type based on stellar parameters (effective temperature, surface gravity, metallicity) PARSEC isochrones model. Our results show that median mass luminosity are 5.4 M$_{\odot}$ log(L/L$_{\odot}$)=3.2 with relative error 21.4$\%$ 71.1$\%$, respectively. A good...
Carbon stars are excellent kinematic tracers of galaxies and play important roles in understanding the evolution Galaxy. Therefore, it is worthwhile to search for them a large amount spectra. In this work, we build new carbon star catalog based on LAMOST DR7 The contains 4542 spectra 3546 stars, identified through line index near-infrared color-color diagrams. Through visual inspection spectra, further subclassify into 925 C--H, 384 C--R, 608 C--N, 1292 Ba stars. However, 437 could not be...