Lexell's Comet

D/1770 L1 (Lexell)
Discovery[1]
Discovered byCharles Messier
Discovery dateJune 14, 1770
Designations
1770 I,
P/Lexell,
Lexell's Comet
Orbital characteristics
Epoch1770-Aug-14
(JD 2367764.5)[2]
Aphelion5.6184 ± 0.0409 AU
Perihelion0.6746 ± 0.003 AU (before Jupiter encounter of 1779)
Semi-major axis3.1465 ± 0.0206 AU
Eccentricity0.7856 ± 0.0013
Orbital period5.58 years (2039 days)
Inclination1.550 ± 0.004°
134.50 ± 0.12
Argument of
periapsis		224.98 ± 0.12
Longitude of
perihelion		359.48 ± 0.24
Last perihelionAugust 14, 1770
Next perihelionunknown/Lost
Physical characteristics
Dimensions~4–30 km
(529668) 2010 JL33
Discovery[3]
Discovered byMLS
Discovery siteMount Lemmon Obs.
Discovery dateMay 6, 2010
Designations
(529668) 2010 JL33
2010 JL33
D/1770 L1 (Lexell) (possibly)
Apollo · NEO · PHA [3][4]
Orbital characteristics [4]
Epoch 2022-Aug-09 (JD 2459800.5)
Uncertainty parameter 0
Observation arc22.75 yr (8,309 d)
Earliest precovery date4 June 1997
Aphelion4.649 AU
Perihelion0.70971 AU
2.6793 AU
Eccentricity0.73512
4.39 yr (1,601 d)
250.87°
0° 13m 28.56s / day
Inclination5.3772°
52.452°
2.32°[2] (good match for Lexell)
7 December 2023
309.87°
Earth MOID0.031 AU (12 LD)
Venus MOID0.00074 AU (110 thousand km)[3]
Mars MOID0.039 AU
Jupiter MOID0.84 AU
TJupiter2.911
Physical characteristics[5]
1.778±0.034 km[6]
9.443±0.002 h[7]
0.047±0.009[6]
17.9[3]

D/1770 L1, popularly known as Lexell's Comet after its orbit computer Anders Johan Lexell, was a comet discovered by astronomer Charles Messier in June 1770.[note 1] It is notable for having passed closer to Earth than any other comet in recorded history, approaching to a distance of only 0.015 astronomical units (2,200,000 km; 1,400,000 mi),[1][8][9] or six times the distance from the Earth to the Moon. The comet has not been seen since 1770 and is considered a lost comet.

Lexell's Comet's 1770 passing still holds the record of closest observed approach of Earth by a comet.[9] However, if approaches deduced from orbit calculations are included, it may have been beaten by a small sungrazing comet, P/1999 J6 (SOHO), which may have passed even closer at about 0.012 AU (1,800,000 km; 1,100,000 mi) from Earth on June 12, 1999,[10] but the uncertainties are around ±1.5 million km[11] as the P/1999 J6 approach was unobserved.[12]

  1. ^ a b Kronk, G. Cometography: D/1770 L1 (Lexell), accessed November 20, 2008.
  2. ^ a b Cite error: The named reference Quan-ZhiYe2018 was invoked but never defined (see the help page).
  3. ^ a b c d Cite error: The named reference MPC-object-529668 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference jpldata-529668 was invoked but never defined (see the help page).
  5. ^ "ALCDEF: Asteroid Photometry Database". alcdef. Retrieved November 24, 2019.
  6. ^ a b Cite error: The named reference Mainzer-2011 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Blaauw-2011 was invoked but never defined (see the help page).
  8. ^ Kronk, G. The Closest Approaches of Comets to Earth, accessed November 20, 20, 2008. It was thought that C/1491 B1 may have approached even closer on February 20, 1491, but its orbit was retracted in 2002 due to a misunderstanding of the records. See Approximate Orbits of Ancient and Medieval Comets: 3. Remarks and Discussion
  9. ^ a b "Closest Approaches to the Earth by Comets". Minor Planet Center. Retrieved January 10, 2018.
  10. ^ "JPL Close-Approach Data: P/1999 J6 (SOHO)" (2010-04-22 last obs (arc=10.9 yr; JFC)). Retrieved June 28, 2012.
  11. ^ Cite error: The named reference J6 was invoked but never defined (see the help page).
  12. ^ Sekanina, Zdenek; Chodas, Paul W. (December 2005). "Origin of the Marsden and Kracht Groups of Sunskirting Comets. I. Association with Comet 96P/Machholz and Its Interplanetary Complex" (PDF). The Astrophysical Journal Supplement Series. 151 (2): 551–586. Bibcode:2005ApJS..161..551S. doi:10.1086/497374. S2CID 85442034. Archived from the original (PDF) on December 16, 2018. Retrieved January 11, 2018.


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