23P/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). It was first discovered by Theodor Brorsen at the Altona Observatory on July 20, 1847, and again by Kaspar Schweizer (Moscow) on August 11, 1847. It was predicted that it would reappear between 1919 and 1922.
|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|
|Semi-major axis||17.07 AU|
|Orbital period||70.52 a|
|Last perihelion||September 11, 1989|
|Next perihelion||June 8, 2059|
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.
- "JPL Small-Body Database Browser: 23P/Brorsen-Metcalf". Jet Propulsion Laboratory. Archived from the original on September 18, 2019. Retrieved October 17, 2011.
last obs. used 1989-09-09
- Seiichi Yoshida (2005-11-09). "23P/Brorsen-Metcalf". Seiichi Yoshida's Comet Catalog. Retrieved February 19, 2012.
- Horizons output. "Observer Table for Comet 23P/Brorsen-Metcalf (1989)". Retrieved February 19, 2012. (Observer Location:@sun)
- Orbital simulation from JPL (Java) / Horizons Ephemeris
- 23P at Kronk's Cometography
- 23P at Kazuo Kinoshita's Comets
- 23P at Seiichi Yoshida's Comet Catalog