Vol. 528
In section 10. Planets and planetary systems

Earth-based detection of the millimetric thermal emission of the nucleus of comet 8P/Tuttle

by J. Boissier, O. Groussin, L. Jorda, P. Lamy, D. Bockelée-Morvan, J. Crovisier, N. Biver, P. Colom, E. Lellouch, and R. Moreno, A&A 528, A54 alt

Little is known about planetary nuclei. Boissier et al. present one of the few detections ever to be made in the radio of the continuum thermal emission from a cometary nucleus, and the first such detection in over 10 years. The detection concerns 8P/Tuttle, a Halley-type comet with a short 13.5 year orbital period. Combining their observation with other datasets (visible and mid-IR), the authors are able to synthesize a nice picture of the cometary nucleus. In particular, they derive low values for the thermal inertia (10 J K-1 m-2 s-1/2) and emissivity (less than 0.8). With more radio observations of cometary nucleii in the future (in particular with ALMA), this study opens the way to a global comparison of the sizes of comets as a function of their orbital properties, origin, etc.