Finding a Risk Corridor For the Asteroid 2020 VV (~12 meters)

By Steven M. Tilley

Map of Asteroid 2020 VV risk corridor crossing the Atlantic, Europe, and Asia — A map of the risk corridor for the ~12m asteroid 2020 VV. Each red dot represents a virtual impactor location in the Earth’s atmosphere. The path crosses the Northeastern Seaboard, Atlantic Ocean, Iberian Peninsula, Middle East, Indian Ocean, India, and Asia. (Screenshot: Guide 9.1)

Background

As of 2020-11-16, the asteroid 2020 VV is listed on the NASA/JPL Sentry risk page (2.6% probability on 2033-10-12.49) and the NEODyS CLOMON2 risk page (1.99% probability on 2033-10-12.488).

Torino Scale: 0 (No Hazard) over the next 100 years.
Palermo Technical Impact Hazard Scale: Below background risk (meaning there is a greater risk from other random asteroids before this date).

For more information on risk pages, see Jon Giorgini’s “Understanding Risk Pages.”

How to Find a Risk Corridor

One of the programs available to amateur observers is Find_Orb (by Bill Gray). It is useful for calculating approximate ephemerides, determining orbits, generating virtual asteroids and impactors, and predicting impact locations. Find_Orb can generate an "asteroid risk corridor" with the help of Guide 9.1.

The Process

As a test of concept, I obtained the observations of 2020 VV from the MPC. I loaded the observations into Find_Orb and ran the Monte Carlo method overnight.

Find_Orb generated the following files: MPCOrb.dat, state.txt, and virtual.txt. These files contained orbits for 7,240 virtual asteroids (VAs), of which 100 were virtual impactors (VIs) (approximately 1.4%). For each, there is a date, time, longitude, and latitude. I placed a copy of virtual.txt and impact.tdf in the Guide directory.

Editing the virtual.txt file configuration — *Note:* Because there were more than nine observations, I edited `virtual.txt` as a workaround (replacing "46 of 46" with "0 of 0") to keep columns aligned. I also edited the `impact.tdf` file.

Guide then generated a map of the asteroid risk corridor, showing where the Line of Variation (LOV) crosses the Earth.

Risk Corridor Visualizations

Below are globe views of the potential impact locations generated by Guide 9.1.

Globe view of risk corridor 4 — Globe views of the asteroid risk corridor. Each red dot indicates where a virtual impactor enters the Earth’s atmosphere.

Download the data: 2020VV-VAs-VIs.XLSX (Google Sheets).

Find_Orb Settings Used

Setting	Value
Selecting perturbers	All
Epoch	2033 Oct 11
Monte Carlo noise	1
Physical model	Standard
Filter out	None

Find_Orb interface showing Monte Carlo settings — Find_Orb computing Monte Carlo variant orbits for asteroid 2020 VV. This method helps determine the uncertainty region where the "real" asteroid is located.

Utility of Virtual Asteroids and Impactors

Virtual Asteroids (VAs) and Virtual Impactors (VIs) are essential for:

Precovery: Finding the object in old images where it should have been.
Recovery: Locating the object when it returns to visibility.
Negative Observations: Using powerful telescopes to rule out specific VIs by observing locations where they should be if they were on an impact trajectory.

Historical Context

Find_Orb has a history of success in this field, having been used to predict impact locations previously. Below is a video demonstrating how to use Find_Orb and Guide 9 to find the impact location of the NEO 2008 TC3.