5D/Brorsen

Infobox Comet
name=5D/Brorsen


discoverer=Theodor Brorsen
discovery_date=26 February, 1846
designations= 1846 III; P/1846 D2; 1857 II; P/1857 F1; 1868 I; 1873 VI; 1879 I
epoch=March 31,1879 ref|LN
semimajor=3.100 AU
perihelion=0.5898 AU
aphelion= 5.610 AU
eccentricity=0.8098
period= 5.461 a
inclination=29.382°
last_p=March 31, 1879
next_p= "Lost"

5D/Brorsen is a comet discovered February 26, 1846, by the Danish astronomer Theodor Brorsen.

The perihelion of 5D/Brorsen was February 25, just a day before its discovery, and maintained the approach to Earth after that, passing closest to Earth on March 27 (at a distance of 0.52 AU). As a result of this close encounter to Earth the comet's coma diameter increased. Johann Friedrich Julius Schmidt estimating it as 3 to 4 arcmin across on March 9, and 8 to 10 arcmin across on the 22nd of that same month. Last seen on April 22, it was stationed about 20 degrees from the north celestial pole. By the end of this first apparition the orbital period was identified as 5.5 years. It was discovered that a close approach to Jupiter in 1842 put in its discovery orbit.

The comet's 5.5 year period would mean that apparitions would alternate between good and poor. As expected, the comet was missed in its 1851 apparition, when the comet only came as close as 1.5 AU to earth.

The comet's orbit was still pretty uncertain, made worse by the fact it had approached Jupiter in 1854. In 1857, Karl Christian Bruhns found a comet on 18 March,1857. Soon an orbit was computed and it was found to be 5D/Brorsen, although predictions were three months off. The comet was followed until June 1857.

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. A very favorable apparition followed in 1879, allowing the comet to be observed for the longest time to date – four months. 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 Marsden, who believed the comet had faded out of existence, but computed the orbit for a very favorable 1973 apparition. Japanese observers made intensive searches for the comet, but nothing turned up. The comet is currently considered lost.

References

# Orbital data taken from this preprint: Neslusan, Lubos: "The identification of asteroid 1996 SK with the extinct nucleus of comet 5D/Brorsen", Memorie della Societa Astronomica Italiana, "Spec. Vol.: Proc. Internat. Conf. held at Palermo, Italy, June 11-16, 2001" [http://astro.savba.sk/~ne/Publications/palermo1.ps (Postscript version)]

External links

* [http://cometography.com/pcomets/005d.html 5D at Kronk's Cometography]