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2018 VP1

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2018 VP1
Discovery[1]
Discovered byZwicky Transient Facility
Discovery sitePalomar Mountain (I43)
Discovery date3 November 2018
Designations
2018 VP1
Orbital characteristics[2]
Epoch 2020-May-31 (JD 2459000.5)
Uncertainty parameter 7
Observation arc12.9 days[3]
Aphelion2.2703 AU (339,630,000 km) (Q)
Perihelion0.90513 AU (135,406,000 km) (q)
1.5877 AU (237,520,000 km) (a)
Eccentricity0.42992 (e)
2.00 yr
300.72° (M)
Inclination3.2419° (i)
39.816° (Ω)
315.12° (ω)
Earth MOID8300 km
Jupiter MOID3.1 AU (460,000,000 km)
Physical characteristics
Dimensions~2 meters (7 feet)[3]
2–4 meters (CNEOS)
30.9[2]

2018 VP1 is an Apollo near-Earth asteroid roughly 2 meters (7 feet) in diameter. The asteroid had a 0.41% chance (1 in 240) of impacting Earth on 2 November 2020 01:12 UT.[3] It was discovered on 3 November 2018 when it was about 0.003 AU (450,000 km; 280,000 mi) from Earth and had a solar elongation of 165 degrees. The asteroid has a short 12.9 day observation arc. It was last observed on 16 November 2018 by the European Southern Observatory Very Large Telescope at apparent magnitude 26 pushing the telescope close to the limiting magnitude.

The JPL Horizons 2 November 2020 nominal Earth approach was estimated as roughly 0.0028 AU (420,000 km; 260,000 mi).[2] The line of variations (LOV, uncertainty region[4]) allowed the asteroid to impact Earth[a] or pass as far away as 0.025 AU (3,700,000 km; 2,300,000 mi).[2] Its diameter of 2–4 meters makes it approximately 100–1000 times less massive than the 20-meter Chelyabinsk meteor.[b] An Earth-impact by this asteroid, assuming it is a common primitive chondrite, might rattle some windows after an airburst and/or drop pebble-sized meteorites on roof tops after dark flight.[5]

Preliminarily results are that nothing was detected via infrasound or atmospheric flash monitors.[6] The asteroid was not visually recovered.

Return

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2018 VP1 has a low 3.2° orbital inclination with respect to the ecliptic plane and an Earth-MOID of only 9700 km.[2] Since the asteroid approached Earth in November 2018 and has a 2.00 year orbital period, the asteroid approached Earth again around 2 November 2020 (±3 days).[2][c] Where Earth will be on a given date is known. However, given the short observation arc and the two years since it was seen at all, the location of the asteroid along its orbit was imprecisely known.

The asteroid intersected Earth's orbit. A slight variation in the known orbit of the asteroid can cause it to be early (NEODyS solution), right on time (Sentry solution), or late (JPL solution).[d] The nominal NEODyS 1 November 2020 23:54 UT Earth approach is 0.0004 AU (60,000 km; 37,000 mi).[7] The Sentry Risk Table showed an estimated 1 in 240 chance of Earth impact on 2 November 2020 1:12 UT.[3] The nominal JPL Horizons 2 November 2020 11:33 UT Earth approach was 0.0028 AU (420,000 km; 260,000 mi) with a 3-sigma uncertainty of ± 4 million km.[2]

Line of variation (LOV) and different closest approaches
Date and time Closest Earth approach Reference
1 November 2020 23:54 0.0004 AU (60,000 km) NEODyS[7]
2 November 2020 01:12 Impact scenario Sentry[3][d]
2 November 2020 11:33 0.0028 AU (420,000 km) JPL SBDB[2]
Animation of 2018 VP1's orbit
Around the Sun – close approach in 2018 and 2020
Around the Earth – close approach in 2018
Around the Earth – assumed close approach in 2020, but numerous other solutions fit
  Sun ·    Earth ·    2018 VP1 ·    Moon

Impact line

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The line of variation (LOV) passed across the Pacific Ocean.[8]

The asteroid came to opposition (opposite the Sun in the sky) at the end of May 2020 at an estimated apparent magnitude of ~31,[9] and as a moving object was much too faint for any telescope to detect. Large ground-based observatories take 10 hours to image a magnitude ~28 object. The Hubble Space Telescope needs 3 weeks of exposure time to image magnitude 31 objects. The November 2020 Earth approach was expected be hidden by the glare of the Sun due to the asteroid's low solar elongation in that time.[9]

Since the asteroid is only about 2 meters (7 feet) in diameter it is too small to do more than create a bolide and common strewn field similar to the Sutter's Mill meteorite or 2014 AA.[10]

It is not categorized as a potentially hazardous object given the estimated size is smaller than the threshold for potentially hazardous objects which are estimated at more than 140 meters in diameter.

See also

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Notes

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  1. ^ The JPL Small-Body Database for 2020-Nov-02 shows a minimum possible distance of 0.000039 AU (5,800 km) from the center of Earth, which is less than the 6371 km radius of Earth.
  2. ^ Assuming the same density and given that the volume of a sphere , 2018 VP1 would have a volume of 4–33 m3 and the Chelyabinsk meteor was ~4200 m3.
  3. ^ The JPL Small-Body Database for 2020-Nov-02 shows the "Time Uncertainty" as 3_07:11 which is 3 days, 7 hours, and 11 minutes.
  4. ^ a b Earth traveling at 30 km/s and with a diameter of 12,800 km, only blocked the path of single virtual impactor for about 8 minutes (30*60*8). Due to a non-Earth like orbit, the virtual asteroids can only impact Earth for about ±10 minutes centered around the virtual impactor at 2 November 2020 01:12 UT. If 2018 VP1 was not crossing Earth's orbit during that time there could be no impact.

References

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  1. ^ "MPEC 2018-V42 : 2018 VP1". IAU Minor Planet Center. 4 November 2018. Retrieved 22 July 2019. (K18V01P)
  2. ^ a b c d e f g h i "JPL Small-Body Database Browser: (2018 VP1)" (last observation: 2018-11-16; arc: 13 days). Jet Propulsion Laboratory. Archived from the original on 21 July 2019. Retrieved 22 July 2019.
  3. ^ a b c d e f "Earth Impact Risk Summary: 2018 VP1". NASA/JPL Near-Earth Object Program Office. Archived from the original on 5 March 2019. Retrieved 22 July 2019.
  4. ^ "Sentry: Earth Impact Monitoring". cneos.jpl.nasa.gov. Retrieved 4 September 2020.
  5. ^ "Can a meteorite dropping fireball be observed all the way to impact with the ground? (Dark Flight)". American Meteor Society. Retrieved 23 August 2020.
  6. ^ Astronomer Michael Busch
  7. ^ a b "2018VP1 Close Approaches". NEODyS (Near Earth Objects – Dynamic Site). Archived from the original on 21 July 2019. Retrieved 22 July 2019.
  8. ^ Path of risk (Risk Corridor) (Peter Thomas, 26 July 2019)
  9. ^ a b "2018VP1 Ephemerides for May–Nov 2020". NEODyS (Near Earth Objects – Dynamic Site). Archived from the original on 21 July 2019. Retrieved 22 July 2019.
  10. ^ Allen, Jeremy (21 August 2020). "An asteroid is on possible collision course with Earth this November: Should we be worried?". ClickOnDetroit. Graham Media Group. Retrieved 22 August 2020.
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