2019 MO

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2019 MO
JPL Orbit Diagram of 2019 MO -2019-06-22 hh21 mm30 UTC.jpg
Orbital diagram of 2019 MO on 22 June 2019
Discovery [1][2]
Discovered byATLAS–MLO (T08)
Discovery siteMauna Loa Obs.
Discovery date22 June 2019
MPC designation2019 MO
NEO · Apollo[2][3]
Orbital characteristics[3]
Epoch 22 June 2019 (JD 2458656.5)
Uncertainty parameter 9 [3] · 7 [2]
Observation arc2.3 h (approx.)[4]
Aphelion4.0116 AU
Perihelion0.9384 AU
2.4750 AU
3.89 yr (1,422 d)
0° 15m 11.16s / day
Earth MOID4.54412×10−7 AU (67.9791 km)
Physical characteristics
Mean diameter

2019 MO, temporarily designated A10eoM1, was a small, harmless 3-meter near-Earth asteroid that impacted Earth on 22 June 2019 at 21:25 UT.[3][4][5][6] It was detected by infrasound and generated a 5-kt bolide off the South coast of Puerto Rico.[5] The strewn field would be spread over the Caribbean Sea.[7]

The Apollo asteroid was inbound approaching a late July perihelion (closest approach to the Sun) when it impacted Earth at 14.9 km/s.


The asteroid was discovered by ATLAS–MLO on 22 June 2019 and was observed four times with an observation arc of 30 minutes. With such a short observation arc it is hard to guess how far (and therefore how large) the object is until more data are available. A fireball was also reported.[3] Using four observations JPL's Scout listed the impact risk as modest,[7] but calculated that the asteroid was about 160 meters[a] in diameter and would pass about 36 LD (14 million km) from Earth.[8] When the Caribbean bolide report came in from the GOES-16 weather satellite it was possible to link the ATLAS astrometry to it. Three additional precovery observations by Pan-STARRS 2 were later located and using seven observations with an observation arc of 2 hours, Scout had a significantly better orbit determination with an impact rating of "elevated".[7] The updated orbit showed that the asteroid was about 1.3 LD (500,000 km) from Earth when it was observed by ATLAS-MLO, 12 hours before impact.


The asteroid came to opposition 175 degrees from the Sun on 17 May 2019 when it had an apparent magnitude of 27.[9] Such a faint apparent magnitude would require a 10 hour image to detect with the largest 8-meter class telescopes in the world. Pan-STARRS is a 1.8-meter class telescope and with 30 second images has a limiting apparent magnitude of around 23. ATLAS has a limiting apparent magnitude closer to 19.[b] The asteroid did not become brighter than apparent magnitude 23 until 19 June when it was about 4 million km from Earth. The asteroid was detected by ATLAS when it was apparent magnitude 18.1.[1]


This bolide was a probable meteorite fall into waters 4.8 km deep. NEXRAD weather radar detected falling meteorites at 21:26:15 UT at 10.6 km above sea level.[10] Signatures consistent with falling meteorites appear in a total of four radar sweeps. Meteorite falls with enough mass to dip into the green pixels are very rare.


It could be an Alinda asteroid originating from the 3:1 mean-motion resonance with Jupiter.[citation needed] Even though 2019 MO has a geometric similarity to the June epsilon Ophiuchids and four other minor meteor showers, it could just as easily be a sporadic meteor that just looks similar by chance.[11] 2019 MO is about 12° away from the concentration of June epsilon Ophiuchids orbits.

Other asteroids discovered before impacting are 2008 TC3, 2014 AA, and 2018 LA.


  1. ^ With only 4 observations over a very short observation arc of 30 minutes, the first Scout solution estimated that the asteroid was bigger and further away. With an estimated absolute magnitude (H) of 21.6 and an assumed albedo of 0.15, the asteroid would have been around 160 meters in diameter.
  2. ^ Magnitude 27 is 40 times fainter than magnitude 23 and magnitude 23 is 40 times fainter than magnitude 19.


  1. ^ a b "MPEC 2019-M72 : 2019 MO". IAU Minor Planet Center. 25 June 2019. Retrieved 25 June 2019.
  2. ^ a b c d "2019 MO". Minor Planet Center. Retrieved 8 July 2019.
  3. ^ a b c d e f "JPL Small-Body Database Browser: (2019 MO)" (2019-06-22 last obs.). Jet Propulsion Laboratory. Retrieved 26 June 2019.
  4. ^ a b Gray, Bill. "Pseudo-MPEC for A10eoM1". Project Pluto. Retrieved 25 June 2019.
  5. ^ a b c Guido, Ernesto. "Small Asteroid (NEOCP A10eoM1) impacted Earth on June 22". Comets & Asteroids news (remanzacco). Retrieved 25 June 2019.
  6. ^ Mack, Eric (25 June 2019). "An asteroid hit Earth right after being spotted by telescope this week". CNET. Retrieved 29 June 2019.
  7. ^ a b c Gal, Roy. "Breakthrough: UH team successfully locates incoming asteroid". University of Hawaii. Retrieved 26 June 2019.
  8. ^ Web archive of Scout: A10eoM1 with 4 observations
  9. ^ "IAWN: 2019 MO Geometry". International Asteroid Warning Network.
  10. ^ "Caribbean Sea near Puerto Rico". Astromaterials Research and Exploration Science Division (ARES@NASA). Retrieved 4 July 2019.
  11. ^ Paul Roggemans (7 July 2019). "June Epsilon Ophiuchids (JEO#459), 2019 Outburst and an Impactor?". Meteor News. Retrieved 8 July 2019.

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