T-type and D-type asteroid, respectively. The rather dark D-types asteroids are common in the outer main belt and among the Jupiter trojan population. Rotation period In October 2011, a rotational lightcurve of Wallia was obtained from photometric observations by Italian amateur astronomers Giovanni Casalnuovo and Benedetto Chinaglia at the Eurac Observatory in southern Tyrol. (They also began observing at the Filzi School Observatory located south of Bolzano). Lightcurve analysis gave a well-defined rotation period of hours with a brightness amplitude of magnitude (). Contrary to the common bimodal shape, the lightcurve for Wallia shows three minima and three maxima. The observers speculate that the unusual shape of the lightcurve might be due either to the body's particular morphology or to the presence of a small companion (the asteroid's possible binary status has not been mentioned since). The results supersede previous observations by Jacques Montier, as well as by Andrea Ferrero (2011), René Roy (2008), L.A. Cieza and L.N. Ciliberti (1999), and Claes-Ingvar Lagerkvist (1979) with period determinations between 10 and 10.5 hours. Diameter and albedo According to the surveys carried out by the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Wallia measures between and kilometers in diameter and its surface has an albedo between and . The Infrared Astronomical Satellite IRAS gives a higher albedo of and consequently a smaller diameter of kilometers, while the Collaborative Asteroid Lightcurve Link assumes an albedo of 0.1485 and derives a diameter of based on an absolute magnitude of 9.5. In 2004 and 2012, Wallia was also subject to two asteroid occultations, timed observations when the asteroid passes in front of a distant star. However the measurements were of poor quality in both cases and gave a best-fit ellipse dimension of () and (), respectively. Notes References External links Lightcurve Database Query (LCDB), at www.minorplanet.info Dictionary of Minor Planet Names, Google books Asteroids and comets rotation curves, CdR – Geneva Observatory, Raoul Behrend Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center 000987 Discoveries by Karl Wilhelm Reinmuth Named minor planets 19221023