Veillet Christian, Parker Joel Wm, Griffin Ian, Marsden Brian, Doressoundiram Alain, Buie Marc, Tholen David J, Connelley Michael, Holman Matthew J
Canada France Hawaii Telescope, Kamuela, Hawaii 96743, USA.
Nature. 2002 Apr 18;416(6882):711-3. doi: 10.1038/416711a.
The recent discovery of a binary asteroid during a spacecraft fly-by generated keen interest, because the orbital parameters of binaries can provide measures of the masses, and mutual eclipses could allow us to determine individual sizes and bulk densities. Several binary near-Earth, main-belt and Trojan asteroids have subsequently been discovered. The Kuiper belt-the region of space extending from Neptune (at 30 astronomical units) to well over 100 AU and believed to be the source of new short-period comets-has become a fascinating new window onto the formation of our Solar System since the first member object, not counting Pluto, was discovered in 1992 (ref. 13). Here we report that the Kuiper-belt object 1998 WW31 is binary with a highly eccentric orbit (eccentricity e approximately 0.8) and a long period (about 570 days), very different from the Pluto/Charon system, which was hitherto the only previously known binary in the Kuiper belt. Assuming a density in the range of 1 to 2 g cm-3, the albedo of the binary components is between 0.05 and 0.08, close to the value of 0.04 generally assumed for Kuiper-belt objects.
最近在一次航天器飞越过程中发现了一颗双小行星，这引起了人们的浓厚兴趣，因为双小行星的轨道参数可以提供质量测量值，而相互掩星则能让我们确定个体大小和整体密度。随后又发现了几颗近地、主带和特洛伊小行星双体。柯伊伯带——从海王星（距离太阳30天文单位）延伸至超过100天文单位的空间区域，被认为是新的短周期彗星的来源——自1992年发现第一个成员天体（不包括冥王星）以来，已成为了解我们太阳系形成的一个迷人新窗口（参考文献13）。在此我们报告，柯伊伯带天体1998 WW31是双体，其轨道高度偏心（偏心率e约为0.8）且周期很长（约570天），这与冥王星/卡戎系统大不相同，冥王星/卡戎系统是此前柯伊伯带中唯一已知的双体。假设密度在1至2克/立方厘米范围内，双体各组成部分的反照率在0.05至0.08之间，接近通常假定的柯伊伯带天体0.04的值。
