5D/Brorsen

5D/Brorsen (also known as Brorsen's Comet or Comet

5D/Brorsen
Brorsen) was a periodic Jupiter-family comet discovered on
February 26, 1846, by Danish astronomer Theodor Brorsen. The
comet was last seen in 1879 and is now considered lost.

Observational history
The comet was discovered on February 26, 1846, by Danish
astronomer Theodor Brorsen. The perihelion of 5D/Brorsen was
February 25, just a day before its discovery, and it passed closest
to Earth on March 27, at a distance of 0.52 AU.[1] As a result of Coma of 5D/Brorsen, as it appeared
on May 14, 1868, drawn by Karl
this close encounter to Earth the comet's coma diameter increased.
Christian Bruhns
Johann Friedrich Julius Schmidt estimated it as 3 to 4 arcminutes
Discovery
across on March 9, and 8 to 10 arcminutes across on the 22nd of
Discovered by Theodor
that same month.[1] On April 22, it was about 20 degrees from the
north celestial pole. By the end of this first apparition the orbital Brorsen
period was calculated as 5.5 years.[1] It was discovered that a Discovery date 26
close approach to Jupiter in 1842 put it in its discovery orbit.[1] February
1846
The comet's 5.5-year period would mean that apparitions would
Designations
alternate between good and poor.[1] As expected, the comet was
Alternative designations 1846 III;
missed in its 1851 apparition, when it only came as close as 1.5
P/1846
AU to Earth. The comet's orbit was still relatively uncertain, made
D2; 1857
worse by its approach to Jupiter in 1854. Karl Christian Bruhns
II;
found a comet on 18 March 1857.[1] Soon an orbit was computed
P/1857
and it was found to be 5D/Brorsen, although predictions were
F1; 1868
three months off.[1] The comet was followed until June 1857, and
I; 1873
the orbit was then well established.[1] Observers reported that the
VI;
comet had a bright, almost star-like nucleus.[2]
1879 I
The comet was missed in 1862, and the next recovery was in Orbital characteristics
1868. A close approach to Jupiter shortened the period enough to Epoch March
make the comet visible in 1873.[1] A very favorable apparition 31, 1879
followed in 1879, allowing the comet to be observed for the [1]

longest time to date – four months.[1] The comet was missed in Aphelion 5.610 AU
1884, due to observing circumstances, but was also missed in
Perihelion 0.5898
1890, a favorable apparition. The next favorable apparition
AU
occurred in 1901, but searches did not locate the comet.
Semi-major axis 3.100 AU
The next serious search was started by Brian G. Marsden in 1963, Eccentricity 0.8098
who believed the comet had faded out of existence, but computed Orbital period 5.461 a
the orbit for a very favorable 1973 apparition.[1] Japanese
Inclination 29.382°
observers made intensive searches for the comet, but nothing Last perihelion March
turned up. This failure to locate the comet, in conjunction with 31,
earlier attempts, lead Marsden to conclude that the comet was 1879[1]
lost.[1] Next perihelion Lost
since
Zdenek Sekanina suggested that the comet underwent a change in
1879
the rotation axis of the nucleus in mid 19th century, resulting to
non-gravitational changes in the orbit, while also mentioned that TJupiter 2.467
there are some evidence that the comet may have
disintergrating.[3] These evidence are the accounts of the large expansion of the coma after perihelion at the
1868 and 1879 apparitions, the presence of condensations in the inner coma during the 1857 and 1868
apparitions and the account by Johann Friedrich Julius Schmidt that on 20 May 1879 the comet was very
faint and lacked a nucleus.[3]

References
1. Kronk, Gary W. (2001–2005). "5D/Brorsen" (http://cometography.com/pcomets/005d.html).
Retrieved 26 December 2005. (Cometography Home Page (http://cometography.com))
2. Gould, B. A. (April 1857). "Second comet of 1857" (https://doi.org/10.1086%2F100581). The
Astronomical Journal. 5: 48. Bibcode:1857AJ......5...48G (https://ui.adsabs.harvard.edu/abs/1
857AJ......5...48G). doi:10.1086/100581 (https://doi.org/10.1086%2F100581).
3. Sekanina, Z. (April 1984). "Disappearance and disintegration of comets" (https://doi.org/10.1
016%2F0019-1035%2884%2990099-X). Icarus. 58 (1): 81–100. Bibcode:1984Icar...58...81S
(https://ui.adsabs.harvard.edu/abs/1984Icar...58...81S). doi:10.1016/0019-1035(84)90099-X
(https://doi.org/10.1016%2F0019-1035%2884%2990099-X).

1. ^ Orbital data taken from this preprint: Neslusan, Lubos: "The identification of asteroid 1996
SK with the extinct nucleus of comet 5D/Brorsen", Memorie della Società Astronomica
Italiana, Spec. Vol.: Proc. Internat. Conf. held at Palermo, Italy, June 11–16, 2001 (Postscript
version) (https://web.archive.org/web/20030717060629/http://astro.savba.sk/~ne/Publication
s/palermo1.ps)

External links
5D at Gary W. Kronk's Cometography (http://cometography.com/pcomets/005d.html)

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