We present time-series CCD photometry of V551 Aur,an eclipsing binary located in the open cluster NGC 2126 that shows δ Scuti-like pulsations.Complete covered light curves in the B and V bands were obtained with high-precision over nine nights.Based on them,a revised orbital period and the first photometric solutions were determined.Our eclipsing light-curve synthesis reveals a detached configuration for the binary system with a mass-ratio of about 0.73,and the mean density of the pulsating primary component was deduced to be about(0.532±0.005)ρ⊙.A frequency analysis of the eclipse-subtracted light curve yields two reliable frequencies at f 1 =7.727013(c/d) and f 2 =15.45403(c/d),respectively.With the help of the derived mean density,mode identification was performed.The result suggests that the primary component of V551 Aur is very probably g-mode oscillations.
Nian LiuXiao-Bin ZhangAn-Bin RenLi-Cai DengZhi-Quan Luo
The electron capture rates of^(55)Co and^(56)Ni in the ultra-strong magnetic field at four typical temperaturedensity points have been calculated using the nuclear shell model and Landau energy levels quantized approximate correction.The results show that the electron capture rates of^(55)Co and^(56)Ni are increased greatly in the ultra-strong magnetic field,and even exceed two orders of magnitude in the range from 4.414×10^(13)G to 2.207×l0^(17)G.The change rate of electron abundance,Y_e,of^(55)Co and^(56)Ni under the condition of B=4.414×l0^(15)G in the magnetar surrounding has been calculated and discussed,the proportions of Y_e of^(55)Co and^(56)Ni in the total Y_e have been reduced by 50percent in all more than the condition without a magnetic field.
The electron capture timescale may be shorter than hydrodynamic timescale in inner iron core of core-collapse supernova according to a recent new idea.Based on the new idea,this paper carries out a numerical simulation on supernova explosion for the progenitor model Ws15M ⊙.The numerical result shows that the size of proto-neutron star has a significant change (decrease about 20%),which may affects the propagation of the shock wave and the final explosion energy.
Based on the new screening model,this paper discusses the influence of superstrong magnetic fields on nuclear energy generation rates on the surface of magnetars.The obtained result shows that the superstrong magnetic fields can increase the nuclear energy generation rates by many orders of magnitude.The enhancement may have a significant influence for further study of the magnetars,especially for the cooling,the x-ray luminosity observation and the evolution of the magnetars.
