Is there horizontal phase propagation of 5-min oscillations at high velocities?

New observations of the photospheric 5-min oscillations are presented which prove that the physical reality of the very high horizontal phase propagation velocities observed in connection with the oscillations cannot be maintained. Instead, a statistical model is proposed to explain the observed phase relations.Mitteilungen aus dem Fraunhofer Institut Nr. 119.     

Observational aspects on a dominant spectral frequency in an airflow over a weeping-lovegrass stand

Mean and fluctuating wind velocities were measured above a flexible stand (weeping-lovegrass). A waving phenomenon Honami appeared over the stand during the observation period. Some spectral parameters were derived from the vertical wind fluctuations. A dependency of frequency on mean horizontal wind velocity was found. The result, n _m = 0.66u, was obtained under the range of wind speeds from 0.9 m s^-1 to 3.1 m s^-1 just above the canopy.     

Numerical Simulation of Accretion Discs in Close Binary Systems andDiscovery of Spiral Shocks

The history of hydrodynamic numerical simulations for accretion disks in close binary systems is reviewed, in which emphasis is placed, in particular, on the facts that spiral shock waves were numerically found in 1986 by researchers including one of the present authors and that spiral structure was discovered in IP Pegasi in 1997 by Steeghs et al. The results of our two and three-dimensional numerical simulations in recent years are then summarized, with comparison being made with observations. This revised version was published online in July 2006 with corrections to the Cover Date.     

High sensitivity SiO maser survey for mira variables

Simultaneous observations of the six transitions of SiO for 106 late-type stars were made. The SiO maser emission was detected in 83 stars. Thev=3 maser emission was detected in eight stars, and the²⁹SiOv=0 emission in six stars. The²⁹SiOv=0 emission is stronger and narrower than that of²⁸SiO, suggesting that the²⁹SiO emission is masing.Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984.     

Accumulation of planetesimals in the solar nebula

Characteristic time scales relevant to the accumulation of planetesimals in a gaseous nebula are examined and the accumulation toward the planets is simulated by numerically solving a growth equation for a mass distribution function. The eccentricity and inclination of planetesimals are assumed to be determined by a balance between excitation due to mutual gravitational scattering and dissipation due to gas drag. Two kinds of mass motion in the radial direction, i.e., diffusion due to mutual scattering and inward flow due to gas drag, are both taken into account. The diffusion is shown to be effective in later stages with a result of accelerating the accumulation. As to the coalescent collision cross section, the usual formula for a binary encounter in a free space is used but the effect of tidal disruption which increases substantially the cross section is taken into account. Numerical results show that the gravitational enhancement factor (i.e., the so-called “Safronov number”), contained in the cross section formula, always takes a value of the order of unity but the accumulation proceeds relatively rapidly owing to the effects of radial diffusion and tidal disruption. That is, a proto-Earth, a proto-Jupiter, and a proto-Saturn with masses of 1×10²⁷ g are formed in 5×10⁶, 1×10⁷, and 1.6×10⁸ years, respectively. Also, a tentative numerical computation for the Neptune formation shows that a proto-Neptune with the same mass requires a long accumulation time, 4.6×10⁹ years. Finally, the other effects which are expected to reduce the above growth times further are discussed.     

The Structure of Young Stellar Jets and Winds Revealed by High Resolution [Fe II] λ1.644μm Line Observations

We present high angular resolution spectra taken along the jets from L1551 IRS 5 and DG Tau obtained with the Subaru Telescope. The position-velocity diagrams of the [Fe II] λ 1.644 μmemission line revealed remarkably similar characteristics for the two sources, showing two distinct velocity components separated from each other in both velocity and space with the entire emission range blueshifted with respect to the stellar velocity. The high velocity component (HVC) has a velocity of –200 ––300 km s^-1 with a narrow line width, while the low velocity component (LVC) is around –100 km s^-1 exhibitinig a broad line width. The HVC is located farther away from the origin and is more extended than the LVC. Our results suggest that the HVC is a well-collimated jet originating from the region close to the star, while the LVC is a widely-opened wind accelerated in the region near the inner edge of the accretion disk.     

Elemental and isotopic abundances of lithium in chondrule constituents in the Allende meteorite

Elemental and isotopic abundances of lithium in chondrule constituents in the Allende CV3 meteorite were determined using secondary ion mass spectrometry. Olivines and mesostasis dominated by a feldspathic phase are depleted in Li ( and , respectively). In contrast, low-Ca pyroxenes and mesostasis dominated by a Na-rich phase are enriched in Li ( and , respectively) and the interchondrule matrix is generally enriched in Li ( on average). The Li isotopic abundance of olivine ranges from to 21. The spatial distributions of elemental and isotopic abundances of Li in olivines within individual chondrules exhibit no systematic pattern. This suggests that the distribution of Li in olivine was not disturbed during aqueous alteration or thermal metamorphism on the Allende meteorite parent body. Although mesostasis is the last crystallizing phase from a chondrule melt and is expected to be enriched in Li, in the Allende meteorite it is generally depleted in Li. We suggest that during aqueous alteration on the CV asteroid, Li in mesostasis was leached out by aqueous fluids. The Li-enriched Na-rich mesostasis was probably produced later by infiltration of Na-rich fluids. It seems likely that aqueous fluids sequestered alkali elements from the Allende-chondrite region in the CV parent asteroid, although significant amounts of Li are preserved in ferrous olivine in the interchondrule matrix.     

Experimental Study of Factors Controlling Sorption of Heavy Metals on Ariake Clay and Implication for Practice

A series of batch tests have been presented to investigate the effects of solid-solution contact time, solid:solution ratio, and pH of solution on sorption of Cd²⁺ and Pb²⁺ on Ariake clay from Kyushu region of Japan. The results show that, among the three investigated factors, solid:solution ratio (SD/SN) seems to be the crucial controlling factor. The Freundlich sorption parameters determined from the batch tests were applied to a typical field landfill in which the Ariake clay was used as soil barrier. The impacts of the landfill were assessed by numerical analysis. Based on the analysis result, the significance of selecting proper solid:solution ratio for determining sorption parameters from batch test has been discussed.