Abstract
BIELA'S COMET IN 1879.—There have been suggestions as to sweeping ephemerides for the recovery of one or other portion of the disintegrated comet of Biela in the present year. It is not, however, easy to decide in what manner, or rather upon what assumptions, calculation can be brought to bear with the greatest chance of success. We know that in 1852 the observed positions of the two nuclei were such that they could be accurately, connected with similar positions at the preceding appearance in 1846, by the application of the perturbations from known causes in the interim, and it is also certain that neither of the nuclei was in the calculated position at the next return but one in 1866, there having been no chance of finding the comet in 1859, from proximity of its geocentric track to the sun's place. In 1865–6 the comet was diligently sought for in and around the position it should have occupied by the elements of 1852, brought up to 1866 by the application of planetary-perturbations during the two revolutions, with some of the most powerful instruments in our observatories, including the refractors at Pulkowa and Copenhagen. D'Arrest, after long search, was convinced that the comet, speaking collectively, could not have passed its perihelion within many days of the time predicted. The conclusion was inevitable that perturbation from some unknown cause must have taken place between 1852 and 1866, and that all clue to the future movement of the comet was for the time lost. In 1872 endeavours to find the comet near its old track were equally unsuccessful, and it was not till the grand meteoric shower on the evening of November 27 in that year that further light was thrown upon the subject. As is well known, the meteors of that great shower were found to be moving in an orbit sensibly identical with that of Biela's comet in 1866. Intersecting, or at least passing very near to the earth's orbit on November 27, the comet must have been descending to a perihelion passage a month later, or about December 27.6; such at least would be the date when the meteoric shower would arrive at its least distance from the sun. In this fact appears the only ground upon which we can now work to obtain an idea of the probable position of the comet in the present year. If we apply Dr. Michez's perturbations from 1852 to 1866 to the late Prof. Hubbard's elaborately-determined elements of the south-following nucleus in 1852 (assumed to be identical with the principal comet in 1846), we find the following orbit for 1866:—
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Our Astronomical Column . Nature 20, 129–130 (1879). https://doi.org/10.1038/020129a0
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DOI: https://doi.org/10.1038/020129a0