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On the metallicity gradient in the Galactic disk

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Research in Astronomy and Astrophysics 2020年第4期20卷 123-128页

作者： Alexander Loktin Maria Popova Astronomical Observatory Ural Federal UniversityEkaterinburgRussia

The problem of the chemical composition gradient in the Galactic disk is studied based on a sample of metallicity estimates of open star clusters,using Gaia DR2-improved distance estimates.A clearly non-monotonic variation was observed in the average metallicity of clusters with increasing Galactocentric *** can clearly see the metallicity jump of 0.22 in[Fe/H]at a Galactocentric distance of about9.5 kpc,which appears to be linked to the outer boundary of the thinnest and youngest component of the Galactic *** absence of a significant metallicity gradient in the internal(R10 kpc)regions of the disk demonstrates the absence of noticeable metal enrichment at times of the order of the ages corresponding to those of the disk regions under *** data show that the disk experiences noticeable metal enrichment only during the starburst *** significant dependence was identified between the average metallicity and the age of the clusters.

关键词： galaxy:general galaxy:disk (galaxy:)open clusters and associations:general

An Asymmetric Galactic Stellar disk Traced by OB-type Stars from LAMOST DR7

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Research in Astronomy and Astrophysics 2024年第6期24卷 38-51页

作者： Xiaopeng Liu Hao Tian Wenyuan Cui Linlin Li Jiaming Liu Zhenyan Huo Yawei Gao Department of Physics Hebei Normal UniversityShijiazhuang 050024China Guo Shoujing Institute for Astronomy Hebei Normal UniversityShijiazhuang 050024China Key Laboratory of Space Astronomy and Technology National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China Institute for Frontiers in Astronomy and Astrophysics Beijing Normal UniversityBeijing 102206China

Using 9943 OB-type stars from LAMOST DR7 in the solar neighborhood,we fit the vertical stellar density profile with the model including a single exponential distribution at different positions(R,Φ).The distributions of the scale heights and scale length show that the young disk traced by the OB-type stars is not *** scale length decreases versus the azimuthal angleΦ,i.e.,from.■kpc withΦ=-3°to■kpc withΦ=9°.Meanwhile we find signal of non-symmetry in the distribution of the scale height of the north and south of the disk *** scale height in the north side shows signal of flaring of the disk,while that of the south disk stays almost constant around h_(s)=130 *** distribution of the displaceeent of the disk plane Z_(0)also shows variance versus the azimuthal angleΦ,which displays significant differences with the warp model constrained by the Cepheid *** also test different values for the position of the Sun,and the distance between the Sun and the Galactic center affects the scale heights and the displacement of the disk significantly,but that does not change our conclusion that the disk is not axisymmetric.

关键词： galaxy:disk galaxies:spiral stars:early-type stars:massive

LAMOST Medium-Resolution Spectral Survey of Galactic Nebulae(LAMOST MRS-N):An overview of scientific goals and survey plan

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Research in Astronomy and Astrophysics 2021年第4期21卷 243-252页

作者： Chao-Jian Wu Hong Wu Wei Zhang Juan-Juan Ren Jian-Jun Chih-Hao Hsia Yu-Zhong Wu Hui Zhu Bin Li Yong-Hui Hou Jun-Lin Wang Shuo-Ran Yu CAS Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China CAS Key Laboratory of Space Astronomy and Technology National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and TechnologyTaipaMacaoChina Purple Mountain Observatory Chinese Academy of SciencesNanjing 210008China University of Science and Technology of China Hefei 230026China Nanjing Institute of Astronomical Optics &TechnologyNational Astronomical ObservatoriesChinese Academy of SciencesNanjing 210042China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China

Since Sep.2018,LAMOST has started the medium-resolution(R~7500)spectral survey(MRS).We proposed the spectral survey of Galactic nebulae,including HⅡregions,HH objects,supernova remnants,planetary nebulae and the special stars with MRS(LAMOST MRS-N).LAMOST MRS-N covers about 1700 square degrees of the northern Galactic plane within 40°

关键词： surveys ISM:general ISM:HII regions ISM:Herbig-Haro objects ISM:planetary nebulae: ISM:supernova remnants galaxy:disk

Search for age pattern across spiral arms of the Milky Way

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Research in Astronomy and Astrophysics 2021年第1期21卷 87-96页

作者： Zhi-Hong He Ye Xu Li-Gang Hou Purple Mountain Observatory Chinese Academy of SciencesNanjing 210023China University of Science and Technology of China Hefei 230026China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China CAS Key Laboratory of FAST National Astronomical Observatories.Chinese Academy of SciencesBeijing 100101China

The age pattern across spiral arms is one of the key observational features utilised to study the dynamic nature of the galaxy’s spiral *** the most updated samples of high-mass star formation region(HMSFR)masers,O stars and open clusters,we investigated their distributions and kinematic properties in the vicinity of the *** found that the Sagittarius-Carina Arm traced by HMSFRs,O stars((?)10 Myr)and young open clusters(200 Myr).These results are consistent with the idea that star formation can be triggered by spiral shocks of density waves,and indicate that the corotation radius of the galaxy is located between the SagittariusCarina Arm and the Local Arm,close to the Solar circle.

关键词： galaxy:disk galaxy:structure galaxy:kinematic and dynamics open clusters and associations:general Stars:massive