双星与变星研究组知识库

We present results derived from four stellar occultations by the plutino object (208996) 2003. AZ(84), detected on 2011 January 8 (single-chord event), 2012 February 3 (multi-chord), 2013 December 2 (single-chord), and 2014 November 15 (multi-chord). Our observations rule out an oblate spheroid solution for 2003. AZ(84)'s shape. Instead, assuming hydrostatic equilibrium, we find that a Jacobi triaxial solution with semiaxes (470 +/- 20) x (383 +/- 10) x (245 +/- 8) km can better account for all our occultation observations. Combining these dimensions with the rotation period of the body (6.75 hr) and the amplitude of its rotation light curve, we derive a density rho = 0.87 +/- 0.01g cm(-3), a geometric albedo p(V) = 0.097 +/- 0.009. A grazing chord observed during the 2014 occultation reveals a topographic feature along 2003. AZ(84) ' s limb, which can be interpreted as an abrupt chasm of width similar to 23. km and depth >8 km, or a smooth depression of width similar to 80. km and depth similar to 13 km (or an intermediate feature between those two extremes).