2011AJ....141...95Y

We obtained near-infrared (NIR; 0.8-2.5 µm) spectra of seven Jovian Trojan asteroids that have been formerly reported to show silicate-like absorption features near 1 µm. Our sample includes the Trojan (1172) Aneas, which is one of the three Trojans known to possess a comet-like 10 µm emission feature, indicative of fine-grained silicates. Our observations show that all seven Trojans appear featureless in high signal-to-noise ratio spectra. The simultaneous absence of the 1 µm band and the presence of the 10 µm emission can be understood if the silicates on (1172) Aneas are iron-poor. In addition, we present NIR observations of five optically gray Trojans, including three objects from the collisionally produced Eurybates family. The five gray Trojans appear featureless in the NIR with no diagnostic absorption features. The NIR spectrum of Eurybates can be best fitted with the spectrum of a CM2 carbonaceous chondrite, which hints that the C-type Eurybates family members may have experienced aqueous alteration.