A Model Atmosphere Analysis of the F6V Star π3 Ori

Model atmosphere analysis, based on Kurucz models has been applied to study the F6V star π³ Ori (=BS1543=HD30652). The following values of the effective temperature, surface gravity and microturbulence velocity were obtained: = 6270±200 K, log g = 3.80.2, ξ_t =3.5±0.5 km/s. The abundances of 10 elements were determined. The resulting element abundances for the π³ Ori were found to be about three times lower with respect to the Sun. From evolutionary calculations we derived a mass, radius and luminosity for π³ Ori of M =1.3 M_⊙, R =2.38 R_⊙, L =7.9 L_⊙. Hence this star should be classified F6IV instead of F6 V. This revised version was published online in July 2006 with corrections to the Cover Date.     

Real and complex spectra – a generalization of WKBJ seismograms

Real plane-waves constitute the building blocks for recently developed spectral techniques in synthetic seismology. While providing numerical convenience, real slowness-spectra model certain wave phenomena in a distributed 'unnatural' way, whereas complex spectra model these phenomena in a compact, more 'natural' way. The theory of complex spectra, called by us the 'Spectral Theory of Transients' (STT) and developed elsewhere, is summarized here and contrasted with the real-spectrum approach. Relying strongly on the theory of analytic functions, STT permits the transient responses to be classified and evaluated according to the singularities they introduce in the complex slowness plane. The method is illustrated for a number of 2-D SH -wave model propagation environments, including interface reflection, head waves, multiple encounters with caustics due to concave boundaries or ducting medium inhomogeneities, and diffraction by structures with edges.     

Blazar天体中光学射电大爆发的频谱演化

本文讨论Ｂｌａｚａｒ天体中光学射电大爆发频谱演化的理论模型．考虑沿喷流传播的相对论性激波所注入或加速的相对论性电子，受到康普顿、同步辐射和绝热膨胀三种损耗，并计及相对论电子能谱的高能截断．假定喷流轴线与观测者方向构成很小角度．文中给出了大爆发频谱三阶段连续演化的特性，即康普顿阶段，同步辐射阶段和绝热膨胀阶段的爆发特性．频谱演化用（Ｓｍ－ｖｍ）关系表达（见图２，图中Ｓｍ为频谱反转流量，ｖｍ为反转频率），它与一些Ｂｌａｚａｒ天体中观测到的典型形式相符合．     

CHARACTERIZATION OF THE EFFECT OF PEAK SHIFTS ON THE PERFORMANCE OF THE KALMAN FILTER IN MULTICOMPONENT ANALYSES

The effect of peak shifts on the performance of a Kalman filter multicomponent analysis algorithm hasbeen investigated.A series of Gaussian test systems were employed to characterize the concentrationestimation errors and the morphology of the on-line residuals(the innovations sequence).Both forwardand reverse filters were used in the generation of the innovations sequences.It was found that thedifference between the forward and reverse innovations sequences gave an accurate indication of thedirection and magnitude of the peak shift.A series of overlapped two-component systems were alsoinvestigated.Again,a correlation between the difference innovations and the degree of the responseshift was observed.The behavior of the Katman filter in fitting the shifted fluorescence emissionspectrum of benzo[a]pyrene was also examined.The response for henzo[a]pyrene in cyclohexanesolution was compared to that obtained on the surface of a reversed phase thin layer chromatographyplate.A red shift of 4 nm was detected for the surface spectrum by observing the difference innovationssequence.This approach holds promise for correction of response shifts in multicomponent systems.