C/2021 A1 (Leonard)

C/2021 A1 (Leonard)
C/2021 A1 (Leonard) on December 28, 2021
Discovery
Discovered byGreg J. Leonard
Discovery date3 January 2021[1]
Designations
C4AGJ62
Orbital characteristics
Observation arc526 days
Orbit typelong period (inbound)
hyperbolic (outbound)
Aphelion≈3700 AU (barycentric epoch 1950)[2]
Perihelion0.6151 AU
Eccentricity0.99966 (barycentric epoch 1950)[2]
1.00004 (barycentric epoch 2100)
Orbital period≈80000 yr (inbound)[2]
Inclination132.68°
255.86°
Argument of
periapsis		225.09°
Last perihelion3 January 2022
Earth MOID0.231 AU (34.6 million km)[3]
Jupiter MOID0.296 AU (44.3 million km)
Comet total
magnitude (M1)		5.3

C/2021 A1 (Leonard) was a long period comet[4] that was discovered by G. J. Leonard at the Mount Lemmon Observatory on 3 January 2021 (a year before perihelion) when the comet was 5 AU (750 million km) from the Sun.[1] It had a retrograde orbit. The nucleus was about 1 km (0.6 miles) across. It came within 4 million km (2.5 million mi) of Venus, the closest-known cometary approach to Venus.[5]

  1. ^ a b Cite error: The named reference MPEC2021-A99 was invoked but never defined (see the help page).
  2. ^ a b c Cite error: The named reference barycenter 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 CBET4907 was invoked but never defined (see the help page).
  5. ^ Weule, Genelle (8 December 2021). "Astronomers anxiously watch Comet Leonard to see if it will live up to predictions as a Christmas treat over Australia". ABC News. Australian Broadcasting Corporation. Retrieved 8 December 2021.