Chinese Astronomy最新文献

We point out that high-energy particle bunches are produced by magnetic annihilation near the light cylinder and hence the pulsed radiation from a neutron star. More explicitly: (1) Magnetic energy may accumulate very rapidly owing to the differential rotation in the non-corotating region near the light cylinder of a neutron star. The scale of the accumulating region is consistent with the observed scale. (2) In a steady-state, the energy is released at the same rate as it is accumulated. We envisage the release to be accomplished by magnetic annihilation. The rate and scale of the high-energy bunches thus obtained agree with the observations. (3) The particle number density in the radiating region we found is much higher than that in the Goldreich-Julian model [1], and thus explaining the observed high density in the Crab pulsar pointed out in [2]. (4) Our model predicts that the γ-radiation and the radio radiation of a given neutron star may have different pulse periods.

In this paper we use the theory of multivariate error analysis to find the expression for the covariance matrix of satellite positions attained by the astronomical method. The dependence of the positional accuracy of the target to the reference stars and on its position within an interpolated segment is discussed and explicit formulae are given.

This paper gives a second-order, analytical solution for the motion of an artificial satellite of the Earth as perturbed by various factors, and the formula for a combined analytical and numerical method. The solution is valid for all eccentricities.

Of the supernovae recorded in history, there are at least two for which re-explosions have been documented. One is the supernova which appeared on 1006 May 1 (Northern $\text{Song}$ Dynasty, Reign $\text{Jingde}$, Year 3) in the asterism $\text{Qiguan}$, south of the lunar mansion $\text{Di}$, which, after 10 years, in 1016 May (Reign $\text{Dazhongxiangfu}$, Year 9) was recorded to have “re-appeared”. The other is the object which appeared by the side of the asterism $\text{Tianjiang}$ of the (sixth) lunar mansion $\text{Wei}$ (the object known in the West as Kepler's supernova), and which after 60 years in 1664 was again recorded as undergoing an explosion. Therefore, for some type of supernovae, there should exist a mechanism of re-explosions.

Proton flare active regions have the common characteristic of an S-shaped neutral line caused by relative movements of sunspots. This observational feature suggested to us a method of estimating the force-free parameter. For three typical active regions we have estimated the variation in the force-free parameter, and assuming a constant force-free parameter, we calculated the structure of the force-free field and the magnetic energy of the potential field. Our calculations show that before the occurence of proton flares, the force-free parameter increases and the magnetic energy of the potential field decreases, this decrease may well be the source for the development of the force-free field, and its magnitude is sufficient for the requirement of the proton flare.

Existing problems in the theory of local convection are analysed. It is shown that the effect of turbulent pressure on the structure and vibrational stability of stars with extensive convective envelopes is not negliable. The physical significance of Henyey's numerical instability in calculations of convective envelopes is elucidated. When the effect of turbulent pressure on hydrostatic equilibrium of stars is considered, we have to abandon the local treatment of convection. We propose a theory of non-local convection based on the dynamic equations of correlation functions.

We have applied the AR spectral analysis to observational series of polar motion, Earth's rotation, tide, and solar activity as well as some artificial sequences, and we confirm that it has a higher resolution than the classical methods of spectral analysis and is thus capable of yielding more information.

Comparing the various statistical equilibrium distributions with the observed distributions in the system of double stars, the following results are obtained: (1) most of the single stars now observed in the Galaxy are not produced through the dissociation of binary stars; (2) at the present stage of the Galaxy the possibility of a single star capturing another to form a binary is much greater than the possibility of a binary dissociating into two single ones; (3) the probability of binary stars decreasing their distance to form a close binary is much greater than that of binary stars increasing their distances.

This paper proposes a view-point on the evolution of single stars, binary stars and multiple stars different from Ambartsumian's.