Comet Yanaka (1988r): A New Class of Carbon-Poor Comet

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Science  25 Sep 1992:
Vol. 257, Issue 5078, pp. 1926-1929
DOI: 10.1126/science.257.5078.1926


As part of a program to determine the chemical composition of a sample population of comets, a very unusual comet, Yanaka (1988r), was observed in January 1989. Although the comet showed the usual emissions of Ol and NH2, it did not display any hint of C2 or CN emission. The comet is depleted in C2 by at least a factor of 100 and in CN by a factor of 25 relative to typical comets. If comets originate from interstellar clouds, Yanaka (1988r) could be an interloper from a cloud of different composition. If Yanaka (1988r) was formed within our solar system, the solar nebula was less uniform than assumed by most present models of formation.