Coordinated Observations of Comet Hale–Bopp between 32 and 860 GHz     

Wink  J. E.  Altenhoff  W. J.  Bieging  J.  Butler  B.  Butner  H.  Haslam  C.G.T.  Kreysa  E.  Martin  R.  Mauersberger  R.  McMullin  J.  Muders  D.  Peters  W.  Schmidt  J.  Schraml  J. B.  Sievers  A.  Stumpff  P.  Von Kapp-Herr  A.  Thum  C.  Zylka  R. 《Earth, Moon, and Planets》1997,77(3):165-165

Earth, Moon, and Planets - The concept of simultaneous multifrequency continuum observations, successfully tested on Comet Hyakutake, was applied to Comet Hale-Bopp, using the Heinrich Hertz...  相似文献   

    

J. E. Wink  W. J. Altenhoff  J. Bieging  B. Butler  H. Butner  C.G.T. Haslam  E. Kreysa  R. Martin  R. Mauersberger  J. McMullin  D. Muders  W. Peters  J. Schmidt  J. B. Schraml  A. Sievers  P. Stumpff  A. Von Kapp-Herr  C. Thum  R. Zylka 《Earth, Moon, and Planets》1997,77(3):165

The concept of simultaneous multifrequency continuum observations, successfully tested on Comet Hyakutake, was applied to Comet Hale-Bopp, using the Heinrich Hertz Submillimeter Telescope (HHT) with the four color bolometer between 250 and 870 GHz, the IRAM 30m telescope at 240 Ghz, the MPIfR 100-m telescope at 32 GHz, and the IRAM interferometer near 90 and 240 GHz. Near-simultaneous measurements were done between February 15 and April 26, 1997, mainly concentrated in mid March shortly before perigee of the comet. The measurements gave the following preliminary results: Interferometer detection of the nuclear thermal emission. If the signal at the longest interferometer spacing of 170 mis due to thermal emission from the nucleus only, its equivalent diameter is ∼49 km. If, however, this signal contains a contribution from a strongly centrally peaked halo distribution(e.g., r⁻² density variation) the diameter may be as low as 35 km. The emission found interferometrically was always 5″ north and 0.1 sec east from the position predicted by Yeoman's solution 55.The comparison of the interferometric continuum emission with the simultanously obtained molecular line observations (reported on this conference) shows the origin of the strongest line emission concentrated on the nucleus. The 30-m observations show a radio halo with a gaussian FWHP of ∼11, corresponding to a diameter of 11000 km at geocentric distance of 1.2 a.u. A spectral index of ∼3.0 for the total signal, which may indicate a smaller mean particle size than for Hyakutake. Assuming an average cometary density of 0.5 gcm⁻³, the mass contained in the nucleus is ∼1$#x2013;3 10¹⁹ g and 10¹² g in the particle halo. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

The general Kepler equation and its solutions     

P. Stumpff 《Celestial Mechanics and Dynamical Astronomy》1987,43(1-4):211-222

My father K. Stumpff (1947, 1949, 1951, 1959, 1962) developed a transcendental equation which replaces the original Kepler equation but is valid for all types of orbits. Other advantages over the classical methods are: a) the independent arguments of the equation follow from the vectors of position and velocity at any instant T_o, where T_o is not necessarily the perihelion time; b) an explicit knowledge of the classical orbital elements is not required; c) transformations of coordinate systems are avoided. The present paper discusses the properties of the general Kepler equation in a wide range of its independent arguments, and it is shown that analytic solutions, existing in special cases, can be used for the numerical solution of general cases. The theory is generalized insofar as it now can handle not only attracting forces but also repulsive ones. As a result of this investigation, FORTRAN subroutines were developed which can be used in connection with any two-body problem for the computation of position and velocity as function of time along any unperturbed orbit.  相似文献