16 April 2021
Perihelion Distance (q)
Aphelion Distance (Q)
Click for NASA orbit diagram
Hills Observatory: 1 January 2013 to 13 August 2019
William R. Brooks (Geneva, New York) was sweeping for comets on the morning of 7 July
1889, when he found this comet in the southeastern sky within the constellation Aquarius.
He described it as faint, with a coma 1 arc minute across and a tail 10 arc minutes long.
Although he was unable to detect any motion before sunrise, Brooks quickly found the comet
the next morning and noted it had moved slightly northward.
On 1 August, E. E. Barnard spotted two small, nebulous companions located 1 and 4.5 arc
minutes away. The next night, Barnard saw four or five additional nebulous objects, all of
which were absent on 3 August. On 4 August, Barnard saw two more objects. The main
nucleus was labelled "A", while those seen on 1 August were labelled "B" and "C". The two
objects seen on 4 August were labelled "D" and "E". Companion "E" was not seen after the
4th, while "D" remained visible for about a week. By mid-August "B" suddenly began to
grow large and diffuse and it was last seen on 5 September. Companion "C" remained
observable until 26 November, while the main nucleus, "A", remained visible nearly until the
time the comet was last seen, which was 13 January 1891.
Another interesting aspect of this comet's first apparition was that it attained a maximum
magnitude of 8. Despite a smaller perihelion distance in the 20th century, the comet has
never become brighter than magnitude 10.5. This abnormal brightening, and the fact that
the comet split into multiple pieces, is blamed on the planet Jupiter. It would seem the
comet passed only 0.001 AU from Jupiter in 1886, actually spending two days within the
orbit of Jupiter's moon Io. The gravitational stresses apparently shattered the comet,
revealing fresh surfaces to interact with the sun's radiation at the 1889 apparition. In
addition to the comet never having attained this brightness since 1889, no trace of any of
the other nuclei have ever been present at later returns.
Since the comet's discovery apparition, it has been missed only twice, in 1918 and 1967,
when the sun-Earth-comet geometry was especially bad, and an encounter with Jupiter in
1921, decreased the perihelion distance from 1.96 AU to 1.86 AU.
28 Sep 14
25 Oct 14
16 Dec 14
19 Jan 15