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A Continuing Controversy: Has the Cometary Nucleus been Resolved?

Published online by Cambridge University Press:  12 April 2016

Zdenek Sekanina

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Barnard (1891) appears to have been the first to recognize the significance of systematic observations of comets at large distances from the sun. His successful tracing of two 1889 comets to heliocentric distances over 5 and even 6 a. u. caused him to notice that some of the short-period comets might be within the reach of the Lick Observatory’s 36-inch refractor throughout their entire orbits around the sun. Although it is clear nowadays that the short-period comets would be a good deal fainter at comparable distances than the two nearly parabolic comets referred to by Barnard, his original idea proved basically correct, except for the necessity of using photographic plates. Periodic Comet Encke was probably detected near aphelion during Barnard’s lifetime, in September 1913 (Barnard 1914a; Marsden and Sekanina 1974). Undisputed images of the comet just several days off aphelion were obtained in 1972 (Roemer 1972; McCrosky and Shao 1972).

Type
Part II
Information
International Astronomical Union Colloquium , Volume 25 , Issue Part2: The Study of Comets , 1976 , pp. 537 - 587
Copyright
Copyright © NASA 1976

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