5D/Brorsen
Semi-major axis 3.100 AU | | |
Eccentricity | 0.8098 | |
---|---|---|
Orbital period | 5.461 a | |
Inclination | 29.382° | |
Last perihelion | March 31, 1879[1] | |
Next perihelion | Lost since 1879 | |
TJupiter | 2.467 |
5D/Brorsen (also known as Brorsen's Comet or Comet Brorsen) was a
. The comet was last seen in 1879 and is now considered lost.Observational history
The comet was discovered on February 26, 1846, by
The comet's 5.5-year period would mean that apparitions would alternate between good and poor.[1] As expected, the comet was missed in its 1851 apparition, when it only came as close as 1.5 AU to Earth. The comet's orbit was still relatively uncertain, made worse by its approach to Jupiter in 1854. Karl Christian Bruhns found a comet on 18 March 1857.[1] Soon an orbit was computed and it was found to be 5D/Brorsen, although predictions were three months off.[1] The comet was followed until June 1857, and the orbit was then well established.[1] Observers reported that the comet had a bright, almost star-like nucleus.[2]
The comet was missed in 1862, and the next recovery was in 1868. A close approach to Jupiter shortened the period enough to make the comet visible in 1873.[1] A very favorable apparition followed in 1879, allowing the comet to be observed for the longest time to date – four months.[1] The comet was missed in 1884, due to observing circumstances, but was also missed in 1890, a favorable apparition. The next favorable apparition occurred in 1901, but searches did not locate the comet.
The next serious search was started by Brian G. Marsden in 1963, who believed the comet had faded out of existence, but computed the orbit for a very favorable 1973 apparition.[1] Japanese observers made intensive searches for the comet, but nothing turned up. This failure to locate the comet, in conjunction with earlier attempts, lead Marsden to conclude that the comet was lost.[1]
Zdenek Sekanina suggested that the comet underwent a change in the rotation axis of the nucleus in mid 19th century, resulting to non-gravitational changes in the orbit, while also mentioned that 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
- ^ a b c d e f g h i j k l m Kronk, Gary W. (2001–2005). "5D/Brorsen". Retrieved 26 December 2005. (Cometography Home Page)
- doi:10.1086/100581.
- ^ .
- ^ 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)
External links