Coordinated radio continuum observations of comets Hyakutake and Hale-Bopp from 22 to 860 GHz
1999; EDP Sciences; Volume: 348; Issue: 3 Linguagem: Inglês
ISSN
1432-0746
AutoresW. J. Altenhoff, John H. Bieging, Bryan Butler, H. M. Butner, R. Chini, C. G. T. Haslam, E. Kreysa, Robert N. Martin, R. Mauersberger, J. P. McMullin, D. Muders, W. L. Peters, J. Schmidt, J. Schraml, A. J. Sievers, P. Stumpff, C. Thum, A. von Kap-Herr, H. Wiesemeyer, J. E. Wink, R. Zylka,
Tópico(s)Astrophysics and Cosmic Phenomena
ResumoWe have observed both Comets Hyakutake and Hale-Bopp close to perigee with several telescopes at frequen- cies between 30 and 860 GHz for an extended period of time. The observed light curves can be described as a simple func- tion of heliocentric and geocentric distances without any out- burst or noticeable variability with time. Our most sensitive diameter estimate for C/Hyakutake re- sulted in an upper limit of 2.1 km. The nuclear diameter of C/Hale-Bopp was determined to 44.2 km after separation from the halo emission. The central part of both halos can be represented by a Gaus- sian with a linear size at half power points of 1870 and 11080 km for Hyakutake and Hale-Bopp, respectively. The spectral index for both comets is = 2.8, indicating a similar particle size distributions in the halo of these comets. For Hale-Bopp the extended emission could be traced to more than 10 5 km from its nucleus. The derived masses, contained in the halo depend strongly on the assumed physical properties of the halo particles. With (1mm) = 75 cm 2 /g, possibly more appropriate for comets, a halo mass of 61 0 10 g is derived for Hyakutake and of 81 0 12 g
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