78P/Gehrels

78P/Gehrels
Discovery
Discovered byTom Gehrels
Discovery dateSeptember 29, 1973
Designations
1973 XI; 1981 XVII; 1989 XVII
Orbital characteristics
EpochMarch 6, 2006
Aphelion5.462 AU
Perihelion2.009 AU
Semi-major axis3.735 AU
Eccentricity0.4622
Orbital period7.22 yr
Inclination6.2530°
Last perihelionApril 2, 2019[1][2]
January 12, 2012[3]
October 27, 2004[1][4]
Next perihelion2026-06-25[5]

78P/Gehrels, also known as Gehrels 2, is a Jupiter-family periodic comet in the Solar System with a current orbital period of 7.22 years.

It was discovered by Tom Gehrels at the Lunar and Planetary Laboratory, Arizona, USA on photographic plates exposed between 29 September and 5 October 1973 at the Palomar Observatory. It had a brightness of apparent magnitude of 15. Brian G. Marsden computed the parabolic and elliptical orbits which suggested an orbital period of 8.76 years, later revising the data to give a perihelion date of 30 November 1963 and orbital period of 7.93 years.[6]

The comet's predicted next appearance in 1981 was observed by W. and A. Cochran at the McDonald Observatory, Texas on 8 June 1981. It was observed again in 1989 and in 1997, when favourable conditions meant that brightness increased to magnitude 12.[6] It has subsequently been observed in 2004 when it reached magnitude 10, 2012, and 2018.[1]

  1. ^ a b c Cite error: The named reference Yoshida-78p was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference NK2102 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference jpldata was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference NK1760 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference MPC was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference kronk was invoked but never defined (see the help page).