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Discovered by Theodor Brorsen and Joel Metcalf
Discovery date July 20, 1847
1847 O1, 1919 Q1, 1989 N1
Orbital characteristics A
Epoch October 1, 1989
Aphelion 33.65 AU
Perihelion 0.478 AU
Semi-major axis 17.07 AU
Eccentricity 0.972
Orbital period 70.52 a[1]
Inclination 19.33°
Last perihelion September 11, 1989[1]
Next perihelion June 8, 2059[2][3]

Comet Brorsen–Metcalf is a periodic comet with an orbital period of 70 years. It fits the classical definition of a Halley-type comet with (20 years < period < 200 years).[1] It was first discovered by Theodor Brorsen (Altona, Germany) on July 20, 1847, and again by Kaspar Schweizer (Moscow) on August 11, 1847, the prediction was made it would return between 1919 and 1922.

On August 21, 1919, the comet was recovered by Joel Hastings Metcalf (Camp Idlewild, Vermont, United States) as 8th magnitude. Additional discoveries were made by Edward Barnard (Yerkes Observatory, Wisconsin, United States) on August 22, Michel Giacobini (Paris, France), Ostrovlev (Theodosia, Crimea) and Selavanov (Saint Petersburg). By the end of September 1919 it was confirmed as being the same as Brorsen's comet.


  1. ^ a b c "JPL Small-Body Database Browser: 23P/Brorsen-Metcalf". Jet Propulsion Laboratory. Retrieved October 17, 2011. last obs. used 1989-09-09 
  2. ^ Seiichi Yoshida (2005-11-09). "23P/Brorsen-Metcalf". Seiichi Yoshida's Comet Catalog. Retrieved February 19, 2012. 
  3. ^ Horizons output. "Observer Table for Comet 23P/Brorsen-Metcalf (1989)". Retrieved February 19, 2012.  (Observer Location:@sun)

External links[edit]

Numbered comets
23P/Brorsen–Metcalf Next