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4581 Asclepius (ə-SKLEE-pee-əs), provisional designation 1989 FC, is a sub-kilometer-sized asteroid, classified as near-Earth object and potentially hazardous asteroid of the Apollo group that makes close orbital passes with Earth. Discovered on 31 March 1989 by American astronomers Henry Holt and Norman Thomas at Palomar Observatory, Asclepius is named after the Greek demigod of medicine and healing.[3][2]

4581 Asclepius
Discovery [1]
Discovered byH. E. Holt
N. G. Thomas
Discovery sitePalomar Obs.
Discovery date31 March 1989
MPC designation(4581) Asclepius
Named after
(Greek mythology)[2]
1989 FC
Apollo · NEO · PHA[1][3]
Orbital characteristics[1]
Epoch 28 May 2014 (JD 2456805.5)
Uncertainty parameter 0
Observation arc27.27 yr (9,959 days)
Aphelion1.3874 AU
Perihelion0.6574 AU
1.0224 AU
1.03 yr (378 days)
0° 57m 12.24s / day
Earth MOID0.0036 AU
Physical characteristics
Dimensions300 m[citation needed]

Asclepius passed by Earth on 22 March 1989, at a distance of 0.00457 AU (684,000 km; 425,000 mi).[4][5] Although this exceeds the Moon's orbital radius, the close pass received attention at that time. "On the cosmic scale of things, that was a close call," said Dr. Henry Holt.[6] Geophysicists estimate that collision with Asclepius would release energy comparable to the explosion of a 600 megaton atomic bomb.[7] The asteroid was discovered 31 March 1989, nine days after its closest approach to the Earth.[8]

Subsequent discoveries revealed that a whole class of such objects exists. Close approaches by objects the size of Asclepius pass by every two or three years, undetected until the start of computerized near-Earth object searches.

On 24 March 2051, the asteroid will pass 0.0123 AU (1,840,000 km; 1,140,000 mi) from the Earth.[4][5] It will be the eighth pass of less than 30 Gm in this century.[4] JPL shows that the uncertainty region of the asteroid will cause it to mostly likely pass from 0.02 AU to 0.17 AU from the Earth in 2135.[4]


  1. ^ a b c d "JPL Small-Body Database Browser: 4581 Asclepius (1989 FC)" (2016-07-06 last obs.). Jet Propulsion Laboratory. Retrieved 13 March 2017.
  2. ^ a b Schmadel, Lutz D. (2007). "(4581) Asclepius". Dictionary of Minor Planet Names – (4581) Asclepius. Springer Berlin Heidelberg. p. 394. doi:10.1007/978-3-540-29925-7_4512. ISBN 978-3-540-00238-3.
  3. ^ a b "4581 Asclepius (1989 FC)". Minor Planet Center. Retrieved 13 March 2017.
  4. ^ a b c d "JPL Close-Approach Data: 4581 Asclepius (1989 FC)" (2015-08-10 last obs (arc=26.36 years)). Retrieved 2016-01-09.
  5. ^ a b "NEODyS-2 Close Approaches for (4581) Asclepius". Near Earth Objects - Dynamic Site. Retrieved 2011-11-08.
  6. ^ "Asteroid's Passing a 'Close Call' for Earth, NASA Says". Los Angeles Times. April 20, 1989. Retrieved 2010-05-07.
  7. ^ Gilchrist, Tom (October 2008). "Effects of an impact event: an analysis of asteroid 1989FC". Geoverse: eJournal of Undergraduate Research in Geography. ISSN 1758-3411. Retrieved 2018-03-01.
  8. ^ Brian G. Marsden (1998-03-29). "How the Asteroid Story Hit: An Aastronomer Reveals How a Discovery Spun Out of Control". Minor Planet Center and Boston Globe newspaper. Retrieved 2011-11-14.

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