首页|An Asymmetric Galactic Stellar Disk Traced by OB-type Stars from LAMOST DR7

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

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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 axisymmetric.The scale length decreases versus the azimuthal angleΦ,i.e.,from 1.14+0.30-0.19 kpc withΦ=-3° to 0.77+0.08-0.06kpc withΦ=9°.Meanwhile we find signal of non-symmetry in the distribution of the scale height of the north and south of the disk plane.The scale height in the north side shows signal of flaring of the disk,while that of the south disk stays almost constant around hs=130 pc.The distribution of the displacement of the disk plane Z0 also shows variance versus the azimuthal angleΦ,which displays significant differences with the warp model constrained by the Cepheid stars.We 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.

Galaxy:diskgalaxies:spiralstars:early-typestars:massive

Xiaopeng Liu、Hao Tian、Wenyuan Cui、Linlin Li、Jiaming Liu、Zhenyan Huo、Yawei Gao

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Department of Physics,Hebei Normal University,Shijiazhuang 050024,China

Guo Shoujing Institute for Astronomy,Hebei Normal University,Shijiazhuang 050024,China

Key Laboratory of Space Astronomy and Technology,National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China

Institute for Frontiers in Astronomy and Astrophysics,Beijing Normal University,Beijing 102206,China

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National Natural Science Foundation of China(NSFC)National Natural Science Foundation of China(NSFC)National Natural Science Foundation of China(NSFC)National Natural Science Foundation of China(NSFC)National Key Basic R&D Program of China via 2019YFA0405500Natural Science Foundation of Hebei ProvinceNatural Science Foundation of Hebei Provinceproject of the Hebei provincial department of science and technology

12173013121030621200304511903012A2021205006A2019205166number 226Z7604

2024

10.1088/1674-4527/ad3dc2

天文和天体物理学研究
中国科学院国家天文台

天文和天体物理学研究

CSTPCD
影响因子：0.406
ISSN：1674-4527
年,卷(期)：2024.24(6)