New Results in Radio Observations of Comets and Asteroids

Dr. Amy Lovell

Agnes Scott College

In the last decade there have been several advances and upgrades for long-wavelength astronomical observatories. These technological improvements have made possible some interesting studies both of cometary comae and of asteroid surfaces. New, more sensitive millimeter and sub-millimeter continuum receivers have enabled rotationally-resolved observations of asteroid thermal emission, suitable for creating lightcurves. For the largest asteroids, these lightcurves are surprisingly high in amplitude well beyond the influence of the nonspherical shape of the bodies. At longer wavelengths, upgrades to the L-band instruments at Arecibo have enabled detection and mapping of 18cm OH spectra from the comae of a wide sample of recent comets in the inner solar system. Long-period comets with more than an order of magnitude lower gas production than that of comet 1P/Halley have been detected and mapped, providing constraints on total gas production, gas outflow velocities, coma asymmetries and excitation conditions. I will present some of our recent unexpected results on both asteroid thermal emission and cometary OH production.