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Jun 19, 2020

A Foofaraw Over a NEO Designated 2018 VP1

Artist's concept of a near-Earth object. Image: Courtesy NASA/JPL-Caltech
Commentary 
Over the years, the tabloids as shown a propensity for raising a foofaraw over Near-Earth Objects. The Close-Approach of 2018 VP1 is only about four months away, and an internet search will reveal several clickbait stories. Many times it appears that tabloid writers pick a random asteroid and writes a "story" about it. At times one must have some background or do some research to see what the more accurate story is.

There is a low probability, 1 in 240, that the two-meter 2018 VP1 will strike the Earth's atmosphere and create spectacular fireballs on 2020-11-02. A test with the Imperial College London's Earth Impact Effects Program reports, "The average interval between impacts of this size somewhere on Earth is 0.2 years". In other words, it would be safe to assume objects the size of 2018 VP1 has impacted Earth's atmosphere since 2018-Nov-03, the date of discovery. The Earth Impact Effects Program also suggests that the fireball is unlikely to do any significant damage. NASA JPL list kinetic energy at impact from 2018 VP1[IF ANY] as ~ 0.00042 MegaTons of TNT. The Chelyabinsk event was 0.4 to 0.5 MegaTons of TNT.

Four times in the past, NEOs were observed by observers of asteroids before impact. These four asteroids(2008 TC3,2014 AA, 2018 LA, and 2019 MO) all were on the safe side when it comes to size.

 Object Date of discovery Date of Impact Size(M)
 2008 TC32008-10-06 2008-10-07 4.1
 2014 AA2014-01-01 2014-01-02 2–4
 2018 LA2018-06-02 2018-06-02 2.6–3.8
 2019 MO2019-06-22 2019-06-22 3–10

One of the programs available to the amateur observers of asteroids and comets is Find_Orb.[By Bill Gray] It is useful for calculating approximate ephemeris, determining approximate orbits, generating virtual asteroids, virtual impactors, predicting impact locations, and many other things. It should be noted IF one uses the wrong setting, one gets an incorrect solution. Find_Orb can generate an "asteroid risk corridor" with the help of Guide 9.1.[By Bill Gray]

Find_orb computing  Monte Carlo variant orbits  for the NEO 2018 VP1. One can use Monte Carlo method to  create virtual asteroids. By using orbits of  the virtual asteroids one can can see where the "real" asteroid could go. If any of virtual asteroids impact the Earth they become  known as  virtual impactors and the is 'Non-Zero' probability of  the real  asteroid hitting the Earth 

My Find_orb Setting

 Selecting perturbers All
 Epoch 2020-11-01.051
 Monte Carlo noise 2
 Physical model Include  SRP
 Filler out 3 worst observations

As a test of concept, I obtained the observations of 2018 VP1 for the Minor Planet Center. I loaded the observations into Find_Orb and had it run the Monte Carlo method all night. Find_orb generated the following files MPCOrb.dat, state.txt, and  virtual.txt. These files had orbits for 129,659 virtual asteroids 200 were virtual impactors( about 0.15%). I place a copy of the virtual.txt file in the Guide directory along with a copy of impact.tdf.(Project Pluto) Then Guide could generate a map of an asteroid risk corridor.

An asteroid (fireball) risk corridor of potential impact for the NEO 2018 VP1, the orange dots is where 200 virtual impactors strike the Earth's atmosphere.

Note: Because there were more than 9 observations, I had to edited virtual.txt to do a workaround. I replace "18 of 21" with "U of O" see edited virtual.txt; this keeps the columns in the right place. I also edited impact.tdf(My) file where I can have more than one risk corridor.



Peter Thomas @ptastro1 also  this path of risk for 2018 VP1 on Twitter

Background

(as of 2020-06-13 )

 
Also see
 

Note this has been edit to fix links and know typos.

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