SIMBAD references

We obtained 49 reflectance spectra of 23 Hilda asteroids in the wavelength ranges 3850-7650 and 3850-10150 Å during two observing runs in 1992. The primitive D-types dominate and comprise 34% of the numbered Hilda asteroids, while 28% and 2% are P and C-types, respectively. This is in contrast to the results of earlier investigations by Tedesco & Gradie (1982Sci...216.1405T) and Gradie et al. (1989, in Distribution of taxonomic classes and the compositional structure of the asteroid belt. Binzel R.P., Gehrels T., Matthews M.S. (Eds.) Asteroid II, Univ. of Arizona Press, Tuscon. p.316) who found fewer D-type asteroids in the Hilda group. We confirm the result by Dahlgren & Lagerkvist (1995A&A...302..907D) that there is a spectral slope - asteroid size relation among the Hilda asteroids, implying a size dependent surface composition. No evidence of absorption features are seen in the spectra of the P and D-types, in particular no features due to phyllosilicates are found, implying that no aqueous alteration of the surfaces has occurred. The absence of C-types within the Hilda group suggests that the C population is confined to smaller heliocentric distances than thought before, with very few C asteroids further out than the Cybele group. The phase reddening effect is absent for the P and D-types observed. Though it is not a Hilda member one spectrum of 279 Thule was obtained and is also presented.