Physical properties of dust in comets, as compared to those of asteroidal and interplanetary material
Résumé
Information about the physical properties of cosmic dust is mainly provided by remote observations. Results about phase angle and wavelength dependence of the polarization of dust in comets are updated, and the phase angle dependence of the (positive) rate of increase of the wavelength dependence is estimated in the visible domain. The same approach leads to a negative rate of increase for S-type asteroids (linear between 30° and 70° for Toutatis), and a possibly positive rate for C-type asteroids. Although observations are still missing, these results provide new constraints for the numerical models and laboratory measurements, including measurements on aggregating dust particles that are anticipated on board the ISS.