Yr. Fernandez et al., X-BAND VLA-ASTERISK OBSERVATIONS OF COMET HYAKUTAKE (C 1996 B2) AND IMPLICATIONS FOR NUCLEAR PROPERTIES/, Planetary and space science, 45(6), 1997, pp. 735-739
The results of our observations during the close approach of comet C/1
996 B2 (Hyakutake) using Very Large Array (VLA) at a wavelength of 3.5
5 cm (X-band) are presented. The scientific goals were to; observe the
thermal microwave continuum from the nucleus and constrain the comet'
s nuclear properties. The 12 h track allows 3-sigma upper limits to be
placed on the emission that are about a factor of four lower than any
previous VLA observation of a comet's continuum. With the caveat that
some assumptions about the microwave emissivity, the temperature, and
the thermal conductivity must be made, the effective radius of Hyakut
ake's nucleus is constrained to be less than 3.0 km, which provides an
addition to the sparse body of knowledge on long-period cometary nucl
ei. Since the observations overlap several of the ROSAT observations o
f this comet, the strength of the microwave flux is estimated from the
X-ray emitting region of the to place constraints on possible emissio
n mechanisms. (C) 1997 Elsevier Science Ltd.