2002 AW197 Statistics

Physical characteristics

The discovery of the Kuiper belt object 2002 AW197 by Trujillo and Brown in January 2002 was announced in MPEC 2002-O30. We measured the diameter and albedo of this object by combining measurements of its reflected light and thermal emission. Photometric observations were performed at the Palomar 60-inch telescope and showed that the object has no detectable lightcurve (Trujillo and Brown, in prep.). Thermal emission observations at 1.2 mm wavelength were made using the Max-Planck Millimeter Bolometer (MAMBO) at the IRAM 30 m telescope on Pico Veleta (Spain). Pointing and ephemeris uncertainties were much less than the 10.6 arcsec beamwidth, and the weather conditions were good with zenith opacities less than ~0.2. Average sensitivity was 30 mJy s1/2, and the KBO was clearly detected with a statistical significance of ~4 sigmas. Our estimate for the diameter of the KBO is 886+115}{-131 km, which makes it slightly smaller than the largest main-belt asteroid 1 Ceres ( ~950 km). The red geometric albedo is estimated to be 0.101+0.038}{-0.022, more than twice the 4% value traditionally assumed for KBOs.

Image Of 2002 AW197

This is probably the first image obtained by astronomers amateurs of such a remote body of the solar system.