Chinese Journal of Astronomy and Astrophysics

Journal Information
ISSN : 1009-9271
Published by: IOP Publishing (10.1088)
Total articles ≅ 814
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Latest articles in this journal

Wei-Kang Zheng, Jin-Song Deng, Meng Zhai, Li-Ping Xin, Yu-Lei Qiu, Jing Wang, Xiao-Meng Lü, Jian-Yan Wei, Jing-Yao Hu
Chinese Journal of Astronomy and Astrophysics, Volume 8, pp 693-699; https://doi.org/10.1088/1009-9271/8/6/08

, Zi Zhu, Da-Li Kong
Chinese Journal of Astronomy and Astrophysics, Volume 8, pp 714-722; https://doi.org/10.1088/1009-9271/8/6/11

Abstract:
With the new Hipparcos data recently released, we reexamine the kinematics in the solar neighborhood. Two different populations of objects, namely the thin-disk O-B5 stars and the thick-disk K-M giants, are selected for tracing the kinematical parameters of the Galaxy. Using a 3-D kinematical model, the components of the solar motion and the Oort constants are derived. The solutions and the kinematics inferred from both types of stars are analyzed. The results obtained with the new data are compared with those from the old Hipparcos data. We conclude that the present solution provides a more reliable estimation of the Oort constants, thanks to the new reduction of the Hipparcos data that provides even more accurate astrometric measurements of stars.
Jian-Ling Wang
Chinese Journal of Astronomy and Astrophysics, Volume 8, pp 643-652; https://doi.org/10.1088/1009-9271/8/6/03

Abstract:
We used the Sloan Digital Sky Survey (SDSS) Data Release 5 (DR5) to study the morphological properties of 1137 nearby infrared (IR) galaxies, most of which are brighter than 15.9 mag in r-band. This sample was drawn from a cross-correlation of the Infra-Red Astronomical Satellite (IRAS) point source catalog redshift survey with DR5 at zlesssim 0.08. Based on this IR galaxy sample, we constructed five volume-limited sub-samples with IR luminosity ranging from 109.5L⊙ to 1012L⊙. By deriving the IR luminosity functions (LF) for different morphological types, we found that normal spiral galaxies are the dominant population below LIR~8×1010 L⊙; while the fraction of barred spiral galaxies increases with increasing IR luminosity and becomes dominant in spiral galaxies beyond LIRsime5×1010L⊙. As the IR luminosity decreases, the IR galaxies become more compact and have lower stellar masses. The analysis also shows that normal spiral galaxies give the dominant contribution to the total comoving IR energy density in the nearby universe, while, in contrast, the contribution from peculiar galaxies is only 39%.
, Shao-Lan Bi
Chinese Journal of Astronomy and Astrophysics, Volume 8, pp 677-685; https://doi.org/10.1088/1009-9271/8/6/06

Abstract:
The aim of this work is to investigate rotation profile of solar-like stars with magnetic fields. A diffusion coefficient of magnetic angular momentum transport is deduced. Rotating stellar models with different mass are computed under the effect of the coefficient. Then rotation profiles are obtained from the theoretical stellar models. The total angular momentum of solar model with only hydrodynamic instabilities is about 13 times larger than that of the Sun at the age of the Sun, and this model can not reproduce quasi-solid rotation in the radiative region. However, not only can the solar model with magnetic fields reproduce an almost uniform rotation in the radiative region, but its total angular momentum is consistent with helioseismic result at the level of 3 $sigma$ at the age of the Sun. The rotation of solar-like stars with magnetic fields is almost uniform in the radiative region. But there is an obvious transition region of angular velocity between the convective core and the radiative region of models with 1.2 - 1.5 $M_{odot}$, where angular velocity has a sharp radial change, which is different from the rotation profile of the Sun and massive stars with magnetic fields. Moreover the changes of the angular velocity in the transition region increase with the increasing in the age and mass.
Lei Wang, Ji-Rong Mao, Shou-Ping Xiang, Ye-Fei Yuan
Chinese Journal of Astronomy and Astrophysics, Volume 8, pp 631-642; https://doi.org/10.1088/1009-9271/8/6/02

Abstract:
Feedback from supernovae (SNe) and from active galactic nuclei (AGN) accom- panies the history of star formation and galaxy evolution. We present an analytic model to explain how and when the SNe and AGN exert their feedback effects on the star formation and galaxy evolution processes. By using SNe and AGN kinetic feedback mechanisms based on the Lambda Cold Dark Matter (LCDM) model, we explore how these feedback mecha- nisms affect the star formation history (SFH), the Near-Infrared Background (NIRB) flux and the cosmological reionization. We find the values of the feedback strengths, � AGN =1 .0 +0.5 −0.3 andSN =0 .04 +0.02 −0.02, can provide a reasonable explanation of most of the observational re- sults, and that the AGN feedback effect on star formation history is quite different from the SNe feedback at high redshifts. Our conclusions manifest quantitatively that these feedback effects decrease star formation rate density (SFRD) and the NIRB flux (in 1.4 − 4.0 μm), and postpone the time of completion of the cosmological reionization.
Lei Zhao, Qiu-He Peng, Xin-Lian Luo
Chinese Journal of Astronomy and Astrophysics, Volume 8, pp 700-706; https://doi.org/10.1088/1009-9271/8/6/09

Abstract:
Sodium overabundance in yellow supergiants has stumped people for more than 20 years. The purpose of this paper is to explore this problem from the perspective of nuclear physics. We investigate carefully the CNO and NeNa cycles that are responsible for sodium production. We investigate some key reactions in the appropriate network. We show whether and how the sodium output can be affected by the rate uncertainties in these reactions. In this way, we evaluate if a reaction is important enough to deserve a better determination of its rate in terrestrial laboratories.
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