The Effects of a Stellar Encounter on a Planetesimal Disk

We investigate the effects of a passing stellar encounter on a planetesimal disk through analytical calculations and numerical simulations, and derive the boundary radius ($a_{\rm planet}$) outside which planet formation is inhibited by disruptive collisions with high relative velocities.Comment: 25 pages, 11 figures, included in 15 tex-files, 7 ps-files and 4 eps-file

Japanese Mapping of Asia-Pacific Areas, 1873-1945: An Overview

Japanese mapping in the Asia-Pacific region up to 1945 calls for scrutiny, because its development was a multifaceted process with military, administrative, political, and cultural dimensions. This article traces the changes in Japanese mapping of overseas areas to the end of World War II and assesses the significance of the resulting maps, called gaihōzu, as sources for East Asian history. As implements of military operation and colonial administration, the gaihōzu were produced during a protracted period by various means under changing circumstances. Expanding military activity also promoted differentiation among the gaihōzu by increasing the use of maps originally produced in foreign countries. In conclusion, the need for detailed cataloging, in combination with chronologically arranged index mapping, is emphasized for the systematic use of the gaihōzu